U.S. patent application number 11/188561 was filed with the patent office on 2006-02-02 for pressure-sensitive adhesive composition, pressure-sensitive adhesive sheets, and surface protecting film.
Invention is credited to Tatsumi Amano, Masahiko Ando, Natsuki Kobayashi.
Application Number | 20060024494 11/188561 |
Document ID | / |
Family ID | 35064622 |
Filed Date | 2006-02-02 |
United States Patent
Application |
20060024494 |
Kind Code |
A1 |
Amano; Tatsumi ; et
al. |
February 2, 2006 |
Pressure-sensitive adhesive composition, pressure-sensitive
adhesive sheets, and surface protecting film
Abstract
An object of the present invention is to provide a
pressure-sensitive adhesive composition which is excellent in
antistatic property of a non-electrification-prevented adherend
(subject to be protected) upon peeling, and has reduced
stainability in an adherend and is excellent in adhesion reliance,
and electrification preventing pressure-sensitive adhesive sheets
using the same. There is provided a pressure-sensitive composition
comprising an ionic liquid, and a (meth)acryl-based polymer
containing, as a monomer component, 0.1 to 100% by weight of a
(meth)acrylic acid alkylene oxide. In addition, there is provided a
pressure-sensitive composition comprising an ionic liquid, and a
polymer containing, as a monomer component, 0.5 to 30% by weight of
a nitrogen-containing monomer and having a glass transition
temperature Tg of no higher than 0.degree. C. Furthermore, there is
provided a pressure-sensitive composition comprising an ionic
liquid, and a (meth)acryl-based polymer containing, as a monomer
component, 0.01 to 20% by weight of a reactive surfactant.
Inventors: |
Amano; Tatsumi;
(Ibaraki-shi, JP) ; Kobayashi; Natsuki;
(Ibaraki-shi, JP) ; Ando; Masahiko; (Ibaraki-shi,
JP) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
35064622 |
Appl. No.: |
11/188561 |
Filed: |
July 25, 2005 |
Current U.S.
Class: |
428/343 ;
156/327; 428/522 |
Current CPC
Class: |
C09J 2301/408 20200801;
Y10T 428/12056 20150115; C09J 2301/302 20200801; Y10T 428/31935
20150401; C09J 7/29 20180101; C09J 7/385 20180101; C09J 133/06
20130101; Y10T 428/28 20150115; C09J 133/08 20130101; C08K 5/34
20130101; C08K 5/19 20130101; C09J 9/02 20130101; G02F 2202/28
20130101; G02F 2202/22 20130101; C08K 5/0075 20130101; C09J 11/06
20130101; Y10T 428/2891 20150115 |
Class at
Publication: |
428/343 ;
428/522; 156/327 |
International
Class: |
B32B 27/30 20060101
B32B027/30; B32B 27/08 20060101 B32B027/08; B32B 7/12 20060101
B32B007/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 26, 2004 |
JP |
2004-217350 |
Dec 3, 2004 |
JP |
2004-351535 |
Jan 19, 2005 |
JP |
2005-011714 |
Apr 7, 2005 |
JP |
2005-110917 |
Apr 27, 2005 |
JP |
2005-129393 |
Claims
1. A pressure-sensitive adhesive composition comprising an ionic
liquid, and a (meth)acryl-based polymer containing, as a monomer
component, 0.1 to 100% by weight of a (meth)acrylic acid alkylene
oxide.
2. The pressure-sensitive adhesive composition according to claim
1, wherein the ionic liquid is at least one kind or more of a
nitrogen-containing onium salt, a sulfur-containing onium salt, and
a phosphorus-containing onium salt.
3. The pressure-sensitive adhesive composition according to claim
1, wherein the ionic liquid contains one or more kinds of cations
represented by the following general formulas (A) to (D). ##STR28##
[in the formula (A), R.sub.a represents a hydrocarbon group of a
carbon number of 4 to 20, and may contain a hetero atom, and
R.sub.b and R.sub.c are the same or different, represent hydrogen
or a hydrocarbon group of a carbon number of 1 to 16, and may
contain a hetero atom, provided that, when a nitrogen atom contains
a double bond, R.sub.c is not present] [in the formula (B), R.sub.d
represents a hydrocarbon group of a carbon number of 2 to 20, and
may contain a hetero atom, and R.sub.e, R.sub.f and R.sub.g are the
same or different, represent hydrogen or a hydrocarbon group of a
carbon number of 1 to 16, and may contain a hetero atom] [in the
formula (C), R.sub.h represents a hydrocarbon group of a carbon
number of 2 to 20, and may contain a hetero atom, and R.sub.i,
R.sub.j and R.sub.k are the same or different, represent a hydrogen
or a hydrocarbon group of a carbon number of 1 to 16, and may
contain a hetero atom] [in the formula (D), Z represents a nitrogen
atom, a sulfur atom, or a phosphorus atom, and R.sub.l, R.sub.m,
R.sub.n and R.sub.o are the same or different, represent a
hydrocarbon group of a carbon number of 1 to 20, and may contain a
hetero atom, provided that, when Z is a sulfur atom, R.sub.o is not
present]
4. The pressure-sensitive adhesive composition according to claim
1, wherein the pressure-sensitive adhesive composition contains an
ethylene oxide group-containing compound.
5. The pressure-sensitive adhesive composition according to claim
4, wherein the ethylene oxide group-containing compound is a
surfactant having an ethylene oxide group.
6. A pressure-sensitive adhesive composition comprising an ionic
liquid, and a polymer containing, as a monomer component, 0.5 to
30% by weight of a nitrogen-containing monomer and having a glass
transition temperature Tg of no higher than 0.degree. C.
7. The pressure-sensitive adhesive composition according to claim
6, wherein the ionic liquid is at least one kind or more of a
nitrogen-containing onium salt, a sulfur-containing onium salt, and
a phosphorus-containing onium salt.
8. The pressure-sensitive adhesive composition according to claim
6, wherein the ionic liquid contains one or more kinds of cations
represented by the following general formulas (A) to (D). ##STR29##
[in the formula (A), R.sub.a represents a hydrocarbon group of a
carbon number of 4 to 20, and may contain a hetero atom, and
R.sub.b and R.sub.c are the same or different, represent hydrogen
or a hydrocarbon group of a carbon number of 1 to 16, and may
contain a hetero atom, provided that, when a nitrogen atom contains
a double bond, R.sub.c is not present] [in the formula (B), R.sub.d
represents a hydrocarbon group of a carbon number of 2 to 20, and
may contain a hetero atom, and R.sub.e, R.sub.f and R.sub.g are the
same or different, represent hydrogen or a hydrocarbon group of a
carbon number of 1 to 16, and may contain a hetero atom] [in the
formula (C), R.sub.h represents a hydrocarbon group of a carbon
number of 2 to 20, and may contain a hetero atom, and R.sub.i,
R.sub.j and R.sub.k are the same or different, represent a hydrogen
or a hydrocarbon group of a carbon number of 1 to 16, and may
contain a hetero atom] [in the formula (D), Z represents a nitrogen
atom, a sulfur atom, or a phosphorus atom, and R.sub.l, R.sub.m,
R.sub.n and R.sub.o are the same or different, represent a
hydrocarbon group of a carbon number of 1 to 20, and may contain a
hetero atom, provided that, when Z is a sulfur atom, R.sub.o is not
present]
9. The pressure-sensitive adhesive composition according to claim
6, wherein the polymer is a (meth)acryl-based polymer containing,
as a main component, one or more kinds of acrylate and/or
methacrylate having an alkyl group of a carbon number of 1 to
14.
10. The pressure-sensitive adhesive composition according to claim
6, wherein the pressure-sensitive adhesive composition contains an
alkylene oxide group-containing compound.
11. A pressure-sensitive adhesive composition comprising an ionic
liquid, and a (meth)acryl-based polymer containing, as a monomer
component, 0.01 to 20% by weight of a reactive surfactant.
12. The pressure-sensitive adhesive composition according to claim
11, wherein the ionic; liquid is at least one kind or more of a
nitrogen-containing onium salt, a sulfur-containing onium salt, and
a phosphorus-containing onium salt.
13. The pressure-sensitive adhesive composition according to claim
11, wherein the ionic liquid contains one or more kinds of cations
represented by the following general formulas (A) to (D). ##STR30##
[in the formula (A), R.sub.a represents a hydrocarbon group of a
carbon number of 4 to 20, and may contain a hetero atom, and
R.sub.b and R.sub.c are the same or different, represent hydrogen
or a hydrocarbon group of a carbon number of 1 to 16, and may
contain a hetero atom, provided that, when a nitrogen atom contains
a double bond, R.sub.c is not present] [in the formula (B), R.sub.d
represents a hydrocarbon group of a carbon number of 2 to 20, and
may contain a hetero atom, and R.sub.e, R.sub.f and R.sub.g are the
same or different, represent hydrogen or a hydrocarbon group of a
carbon number of 1 to 16, and may contain a hetero atom] [in the
formula (C), R.sub.h represents a hydrocarbon group of a carbon
number of 2 to 20, and may contain a hetero atom, and R.sub.i,
R.sub.j and R.sub.k are the same or different, represent a hydrogen
or a hydrocarbon group of a carbon number of 1 to 16, and may
contain a hetero atom] [in the formula (D), Z represents a nitrogen
atom, a sulfur atom, or a phosphorus atom, and R.sub.l, R.sub.m,
R.sub.n and R.sub.o are the same or different, represent a
hydrocarbon group of a carbon number of 1 to 20, and may contain a
hetero atom, provided that, when Z is a sulfur atom, R.sub.o is not
present]
14. The pressure-sensitive adhesive composition according to claim
11, wherein the reactive surfactant is a reactive surfactant having
an ethylene oxide group.
15. A pressure-sensitive adhesive layer, wherein the
pressure-sensitive adhesive composition as defined in claim 1 is
crosslinked.
16. A pressure-sensitive adhesive sheet comprising a
pressure-sensitive adhesive layer containing a pressure-sensitive
adhesive composition as defined in claim 1 on one side or both
sides of a support.
17. A surface protecting film comprising a pressure-sensitive
adhesive layer, which is formed by crosslinking a
pressure-sensitive adhesive composition as defined in claim 1 on
one side or both sides of a support which is provided with an
antistatic-treated plastic film.
18. A pressure-sensitive adhesive layer, wherein the
pressure-sensitive adhesive composition as defined in claim 6 is
crosslinked.
19. A pressure-sensitive adhesive sheet comprising a
pressure-sensitive adhesive layer containing a pressure-sensitive
adhesive composition as defined in claim 6 on one side or both
sides of a support.
20. A surface protecting film comprising a pressure-sensitive
adhesive layer, which is formed by crosslinking a
pressure-sensitive adhesive composition as defined in claim 6 on
one side or both sides of a support which is provided with an
antistatic-treated plastic film.
21. A pressure-sensitive adhesive layer, wherein the
pressure-sensitive adhesive composition as defined in claim 11 is
crosslinked.
22. A pressure-sensitive adhesive sheet comprising a
pressure-sensitive adhesive layer containing a pressure-sensitive
adhesive composition as defined in claim 11 on one side or both
sides of a support.
23. A surface protecting film comprising a pressure-sensitive
adhesive layer, which is formed by crosslinking a
pressure-sensitive adhesive composition as defined in claim 11 on
one side or both sides of a support which is provided with an
antistatic-treated plastic film.
24. A pressure-sensitive adhesive composition comprising an ionic
liquid and a polymer selected from the group consisting of (i) a
(meth)acryl-based polymer containing, as a monomer component, 0.1
to 100% by weight of a (meth)acrylic acid alkylene oxide, (ii) a
polymer containing, as a monomer component, 0.5 to 30% by weight of
a nitrogen-containing monomer and having a glass transition
temperature Tg of no higher than 0.degree. C., and (iii) a
(meth)acryl-based polymer containing, as a monomer component, 0.01
to 20% by weight of a reactive surfactant.
25. A surface protecting film comprising (a) a support provided
with an antistatic-treated plastic film; and (b) a
pressure-sensitive adhesive layer constituted by a crosslinked
product of the pressure-sensitive adhesive composition of claim 24,
said pressure-sensitive adhesive layer being formed on one side or
both sides of the support.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a pressure-sensitive
adhesive composition having antistatic property, and
pressure-sensitive adhesive sheets and a surface protecting film
obtained by formulating into a form of a sheet or a tape using the
composition.
[0003] Pressure-sensitive sheets comprising an antistatic
pressure-sensitive adhesive composition of the present invention is
suitably used in plastic products on which static electricity is
easily generated. Among them, particularly, the sheets are useful
as antistatic pressure-sensitive adhesive sheets used in utilities
disliking static electricity such as an electronic instrument, as
well as a surface protecting film.
[0004] 2. Description of the Related Art
[0005] A surface protecting film is generally used for the purpose
of preventing a scratch or a stain produced at processing or
conveyance of a subject to be protected by applying to a subject to
be protected via a pressure-sensitive adhesive layer coated on a
protecting film side. For example, for the purpose of preventing a
scratch or a stain, a surface protecting film is applied to an
optical member such as a polarizing plate and a wavelength plate
used in a panel of a liquid crystal display via a
pressure-sensitive adhesive layer.
[0006] When a liquid crystal display is produced with these optical
members, since a surface protecting film become unnecessary, it is
peeled and removed from an optical member. Since the aforementioned
optical member, pressure-sensitive adhesive, and surface protecting
film are constructed of a plastic material, they have high
electrical insulating property and generate static electricity upon
friction or peeling. Therefore, also when a surface protecting film
is peeled from an optical member, static electricity is generated.
Therefore, also when a protecting film is peeled from an optical
member such as a polarizing plate, static electricity is generated.
When a voltage is applied to a liquid crystal in the state where
static electricity remains, orientation of a liquid crystal
molecule is lost, and a defect of a panel is generated. Then, in
order to prevent such the disadvantage, a surface protecting film
is subjected to various antistatic treatments.
[0007] Previously, as an attempt to suppress the aforementioned
electrification of static electricity, for example, a method of
preventing electrification by adding a low-molecular surfactant to
a pressure-sensitive adhesive, and transferring a surfactant from a
pressure-sensitive adhesive to an adherend has been disclosed (for
example, see Patent Publication 1). However, the low-molecular
surfactant is easily bled on a surface of a pressure-sensitive
adhesive agent and, when applied to a protecting film, staining of
an adherend is feared. Therefore, when a pressure-sensitive
adhesive with a low-molecular surfactant added thereto is applied
to a protecting film for an optical member, there is a problem that
optical property of an optical member is deteriorated.
[0008] In addition, a method of adding an antistatic agent
comprising polyether polyol and alkali metal salt to an acryl
pressure-sensitive adhesive to suppress an antistatic agent from
bleeding on a surface of a pressure-sensitive adhesive has been
disclosed (for example, see Patent Publication 2). However, also in
this method, bleeding of an antistatic agent is not avoided, and it
has been found out that, when applied to a surface protecting film,
staining of an adherend occurs with time or under a high
temperature.
[0009] Furthermore, a method for providing antistatic to the base
polymer itself of a pressure-sensitive adhesive composition is
disclosed as a means for reducing the aforementioned staining (see,
for example, Patent Publication 3). In this disclosure, a
pressure-sensitive adhesive composition made of a (meth)acryl-based
polymer that contains a reactive surfactant is cited. However,
great effects of suppressing the peeling electrification voltage on
the adherend side that has not been electrification-prevented,
according to this method, are not recognized, and as a result, it
has been found that it is difficult to reduce staining and at the
same time suppress the peeling electrification voltage on the
adherend side that has not been electrification-prevented.
[0010] [Patent Publication 1] JP-A No.9-165460
[0011] [Patent Publication 2] JP-A No.6-128539
[0012] [Patent Publication 3] JP-A No.9-208910
SUMMARY OF THE INVENTION
[0013] In light of such the circumstances, an object of the present
invention is to solve problems to provide an antistatic
pressure-sensitive adhesive composition which is excellent in
antistatic property of a non-electrification-prevented adherend
(subject to be protected) upon peeling, and has reduced
stainability in an adherend and is excellent in adhesion reliance,
and electrification preventing pressure-sensitive adhesive sheets
using the same.
[0014] In addition, an object of the present invention is to solve
problems to provide an antistatic pressure-sensitive adhesive
composition which is excellent in antistatic property of a
non-electrification-prevented adherend (subject to be protected)
upon peeling, and has reduced stainability in an adherend,
suppresses occurrence of peeling off from an adherend, and is
excellent in adhesion reliance, and electrification preventing
pressure-sensitive adhesive sheets using the same.
SUMMARY OF THE INVENTION
[0015] In order to solve the aforementioned problems, the present
inventors intensively studied and, as a result, found out that the
aforementioned object can be attained by a pressure-sensitive
adhesive composition shown below, which resulted in completion of
the present invention.
[0016] That is, a pressure-sensitive adhesive composition of the
present invention is characterized in that it contains an ionic
liquid, and a (meth)acryl-based polymer containing, as a monomer
component, 0.1 to 100% by weight of a (meth)acrylic acid alkylene
oxide.
[0017] According to the pressure-sensitive adhesive composition of
the present invention, as shown in results of Example I, since 0.1
to 100% by weight of a (meth)acrylic acid alkylene oxide is a
monomer component, and an ionic liquid is further contained, in a
pressure-sensitive adhesive layer obtained by crosslinking this,
staining property on an adherend (subject to be protected) is
reduced, and antistatic property of an adherend (subject to be
protected) upon peeling becomes excellent. Although details of
reasons why a crosslinked base polymer using the aforementioned
monomer component as a main component manifests such the property
are not clear, it is presumed that, by coordination of an ether
group in an acrylic acid alkylene oxide with an ionic liquid,
bleeding of an ionic liquid becomes difficult, and both of
excellent antistatic property and low staining property are
realized.
[0018] The ionic liquid in the present invention refers to a melt
salt (ionic compound) exhibiting the liquid state at room
temperature (25.degree. C.).
[0019] According to the present invention, by use of the
aforementioned ionic liquid as an antistatic agent, a
pressure-sensitive adhesive composition in which bleeding of an
antistatic agent is suppressed, and adhesion reliance to an
adherend with time or even under a high temperature is excellent,
is obtained. Although the reason why bleeding can be suppressed
using an ionic liquid is not clear, it is presumed to be the high
compatibility with a base polymer in comparison with surfactants or
the like. In addition, an ionic liquid itself exhibits high
conductivity, and therefore, sufficient antistatic properties can
be gained, even when staining on a surface of an adherend is
microscopic.
[0020] In addition, the aforementioned ionic liquids are preferably
in the state of liquid at room temperature, and therefore, addition
to, diffusion in, and dissolving in pressure-sensitive adhesive
compositions can be easily carried out, in comparison with solid
salts. Furthermore, the ionic liquid has no vapor pressure
(non-volatile), and therefore, it does not vanish with time, and
antistatic properties are maintained.
[0021] In the present invention, a (meth)acryl-based polymer
containing, as a monomer component, 0.1 to 100% by weight of a
(meth)acrylic acid alkylene oxide is used as a base polymer. The
(meth)acryl-based polymer in the present invention refers to an
acryl-based polymer and/or a methacryl-based polymer. In addition,
the (meth)acrylic acid alkylene oxide refers to an acrylic acid
alkylene oxide and/or a methacrylic acid alkylene oxide, and, the
(meth)acrylate refers to an acrylate and/or a methacrylate.
[0022] In the foregoing, it is preferable that the ionic liquid is
one or more kinds of a nitrogen-containing onium salt, a
sulfur-containing onium salt, and a phosphorus-containing onium
salt. In particular, it is preferable that the ionic liquid
contains one or more kinds of cations represented by the following
general formulas (A) to (D). By an ionic liquids having these
cations, further excellent antistatic ability is obtained. ##STR1##
[0023] [in the formula (A), R.sub.a represents a hydrocarbon group
of a carbon number of 4 to 20, and may contain a hetero atom, and
R.sub.b and R.sub.c are the same or different, represent hydrogen
or a hydrocarbon group of a carbon number of 1 to 16, and may
contain a 5 hetero atom, provided that, when a nitrogen atom
contains a double bond, R.sub.c is not present] [0024] [in the
formula (B), R.sub.d represents a hydrocarbon group of a carbon
number of 2 to 20, and may contain a hetero atom, and R.sub.e,
R.sub.f and R.sub.g are the same or different, represent hydrogen
or a hydrocarbon group of a carbon number of 1 to 16, and may
contain a hetero atom] [0025] [in the formula (C), R.sub.h
represents a hydrocarbon group of a carbon number of 2 to 20, and
may contain a hetero atom, and R.sub.i, R.sub.j and R.sub.k are the
same or different, represent a hydrogen or a hydrocarbon group of a
carbon number of 1 to 16, and may contain a hetero atom] [0026] [in
the formula (D), Z represents a nitrogen atom, a sulfur atom, or a
phosphorus atom, and R.sub.l, R.sub.m, R.sub.n and R.sub.o are the
same or different, represent a hydrocarbon group of a carbon number
of 1 to 20, and may contain a hetero atom, provided that, when Z is
a sulfur atom, R.sub.o is not present]
[0027] In addition, it is preferable that the pressure-sensitive
adhesive composition contains an ethylene oxide group-containing
compound. By using such the ethylene oxide group-containing
compound, more excellent antistatic property is obtained.
[0028] Furthermore, it is preferable that the ethylene oxide
group-containing compound is a surfactant having an ethylene oxide
group. By using a surfactant having an ethylene oxide group,
compatibility with an ionic liquid and a base polymer is further
improved, bleeding onto an adherend is suppressed, and a low
staining pressure-sensitive adhesive composition is obtained.
[0029] In addition, a pressure-sensitive adhesive composition of
the present invention is characterized in that it contains an ionic
liquid, and a polymer containing, as a monomer component, 0.5 to
30% by weight of a nitrogen-containing monomer and having a glass
transition temperature Tg of no higher than 0.degree. C.
[0030] According to the pressure-sensitive adhesive composition of
the present invention, as shown in results of Example II, since 0.5
to 30% by weight of a nitrogen-containing monomer is a monomer
component and a polymer having a glass transition temperature Tg of
no higher than 0.degree. C. as a base polymer, and an ionic liquid
is further contained, in a pressure-sensitive adhesive layer
obtained by crosslinking this, staining property on an adherend
(subject to be protected) is reduced, occurrence of peeling off can
not be realized, and antistatic property of an adherend (subject to
be protected) upon peeling becomes excellent. Although details of
reasons why a crosslinked base polymer using the aforementioned
monomer component as a main component manifests such the property
are not clear, it is presumed that, by coordination of a nitrogen
atom in a nitrogen-containing monomer with an ionic liquid,
bleeding of an ionic liquid becomes difficult, and both of
excellent antistatic property and low staining property are
realized.
[0031] In the present invention, the (meth)acryl-based polymer
containing, as a monomer component, 0.5 to 30% by weight of a
nitrogen-containing monomer and having a glass transition
temperature Tg of no higher than 0.degree. C. is used as a base
polymer.
[0032] In addition, a nitrogen-containing monomer in the present
invention refers to a polymerizable monomer containing one or more
nitrogen atoms in the monomer structure thereof. Examples thereof
include an amide group containing monomer, an amino group
containing monomer, an imide group containing monomer, a cyano
group containing monomer, acryloylmorpholine, and the like.
[0033] In the foregoing, it is preferable that the ionic liquid is
one or more kinds of a nitrogen-containing onium salt, a
sulfur-containing onium salt, and a phosphorus-containing onium
salt. In particular, it is preferable that the ionic liquid
contains one or more kinds of cations represented by the following
general formulas (A) to (D). By an ionic liquids having these
cations, further excellent antistatic ability is obtained. ##STR2##
[0034] [in the formula (A), R.sub.a represents a hydrocarbon group
of a carbon number of 4 to 20, and may contain a hetero atom, and
R.sub.b and R.sub.c are the same or different, represent hydrogen
or a hydrocarbon group of a carbon number of 1 to 16, and may
contain a hetero atom, provided that, when a nitrogen atom contains
a double bond, R.sub.c is not present] [0035] [in the formula (B),
R.sub.d represents a hydrocarbon group of a carbon number of 2 to
20, and may contain a hetero atom, and R.sub.e, R.sub.f and R.sub.g
are the same or different, represent hydrogen or a hydrocarbon
group of a carbon number of 1 to 16, and may contain a hetero atom]
[0036] [in the formula (C), R.sub.h represents a hydrocarbon group
of a carbon number of 2 to 20, and may contain a hetero atom, and
R.sub.i, R.sub.j and R.sub.k are the same or different, represent a
hydrogen or a hydrocarbon group of a carbon number of 1 to 16, and
may contain a hetero atom] [0037] [in the formula (D), Z represents
a nitrogen atom, a sulfur atom, or a phosphorus atom, and R.sub.l,
R.sub.m, R.sub.n and R.sub.o are the same or different, represent a
hydrocarbon group of a carbon number of 1 to 20, and may contain a
hetero atom, provided that, when Z is a sulfur atom, R.sub.o is not
present]
[0038] In addition, it is preferable that the aforementioned
polymer is a (meth)acryl-based polymer containing, as a main
component, one or more kinds of (meth)acrylate having an alkyl
group of a carbon number of 1 to 14. By these (meth)acryl-based
polymers, balance of compatibility with an ionic liquid and a base
polymer becomes better, and adhering property can be sufficiently
maintained.
[0039] In aforementioned pressure-sensitive adhesive composition,
it is preferable that the pressure-sensitive adhesive composition
contains an alkylene oxide group-containing compound. By using such
the alkylene oxide group-containing compound, more excellent
antistatic property is obtained.
[0040] Furthermore, a pressure-sensitive adhesive composition of
the present invention is characterized in that it contains an ionic
liquid, and a (meth)acryl-based polymer containing, as a monomer
component, 0.01 to 20% by weight of a reactive surfactant.
[0041] According to the pressure-sensitive adhesive composition of
the present invention, as shown in results of Example III, since
0.01 to 20% by weight of a reactive surfactant is a monomer
component, and an ionic liquid is further contained, in a
pressure-sensitive adhesive layer obtained by crosslinking this,
staining property on an adherend (subject to be protected) is
reduced, and antistatic property of an adherend (subject to be
protected) upon peeling, especially antistatic property of an
adherend which has not electrification-prevented upon peeling,
becomes excellent. Although details of reasons why a crosslinked
base polymer using the aforementioned monomer component as a main
component manifests such the property are not clear, it is presumed
that, by coordination of an ester group and/or an ether group in a
reactive surfactant with an ionic liquid, bleeding of an ionic
liquid becomes difficult, and both of excellent antistatic property
and low staining property are realized.
[0042] The reactive surfactant in the present invention refers to a
reactive surfactant having a reactive unsaturated bond.
[0043] In the present invention, the (meth)acryl-based polymer
containing, as a monomer component, 0.01 to 20% by weight of a
reactive surfactant is used as a base polymer.
[0044] In the foregoing, it is preferable that the ionic liquid is
one or more kinds of a nitrogen-containing onium salt, a
sulfur-containing onium salt, and a phosphorus-containing onium
salt. In particular, it is preferable that the ionic liquid
contains one or more kinds of cations represented by the following
general formulas (A) to (D). By an ionic liquids having these
cations, further excellent antistatic ability is obtained. ##STR3##
[0045] [in the formula (A), R.sub.a represents a hydrocarbon group
of a carbon number of 4 to 20, and may contain a hetero atom, and
R.sub.b and R.sub.c are the same or different, represent hydrogen
or a hydrocarbon group of a carbon number of 1 to 16, and may
contain a hetero atom, provided that, when a nitrogen atom contains
a double bond, R.sub.c is not present] [0046] [in the formula (B),
R.sub.d represents a hydrocarbon group of a carbon number of 2 to
20, and may contain a hetero atom, and R.sub.e, R.sub.f and R.sub.g
are the same or different, represent hydrogen or a hydrocarbon
group of a carbon number of 1 to 16, and may contain a hetero atom]
[0047] [in the formula (C), R.sub.h represents a hydrocarbon group
of a carbon number of 2 to 20, and may contain a hetero atom, and
R.sub.i, R.sub.j and R.sub.k are the same or different, represent a
hydrogen or a hydrocarbon group of a carbon number of 1 to 16, and
may contain a hetero atom] [0048] [in the formula (D), Z represents
a nitrogen atom, a sulfur atom, or a phosphorus atom, and R.sub.l,
R.sub.m, R.sub.n and R.sub.o are the same or different, represent a
hydrocarbon group of a carbon number of 1 to 20, and may contain a
hetero atom, provided that, when Z is a sulfur atom, R.sub.o is not
present]
[0049] In addition, it is preferable that the aforementioned
reactive surfactant contains an ethylene oxide group. By using the
reactive surfactant that contains an ethylene oxide group, a
pressure-sensitive adhesive composition having more low-staining
property is provided.
[0050] Although the reason why such properties are exhibited by
using the reactive surfactant that contains an ethylene oxide group
is not clear, it is presumed that the ether group of the reactive
surfactant more strongly coordinates the ionic liquid than ester
groups, and thereby, bleeding of the ionic liquid is
restricted.
[0051] On the other hand, a pressure-sensitive adhesive layer of
the present invention is characterized in that the aforementioned
pressure-sensitive adhesive composition is crosslinked. By
performing crosslinking by appropriately regulating a
constitutional unit and a constitutional ratio of a
(meth)acryl-based polymer, selection of a crosslinking agent, and
an addition ratio, a surface protecting film more excellent in heat
resistance and weather resistance can be obtained.
[0052] In addition, a pressure-sensitive adhesive sheet is
characterized in that the sheet has a pressure-sensitive adhesive
layer, which is formed by crosslinking a pressure-sensitive
adhesive composition as defined above on one side or both sides of
a support. According to the pressure-sensitive adhesive sheet of
the present invention, since the pressure-sensitive adhesive
composition of the present invention exerting the aforementioned
action and effect is used, electrification of an adherend (subject
to be protected) which has not electrification-prevented can be
prevented upon peeling, and a pressure-sensitive adhesive sheet
which can reduce staining property on an adherend (subject to be
protected),and excellent adhesion reliance can be obtained.
[0053] In particular, according to the aforementioned
pressure-sensitive adhesive sheet of the present invention which
contains, as a monomer component, 0.5 to 30% by weight of a
nitrogen-containing monomer and has a glass transition temperature
Tg of no higher than 0.degree. C., since the pressure-sensitive
adhesive composition of the present invention exerting the
aforementioned action and effect is used, electrification of an
adherend (subject to be protected) which has not
electrification-prevented can be prevented upon peeling, and a
pressure-sensitive adhesive sheet which can reduce staining
property on an adherend (subject to be protected), occurrence of
peeling off can not be realized, and excellent adhesion reliance
can be obtained.
[0054] Furthermore, when the pressure-sensitive adhesive
composition of the present invention is applied to a surface
protecting film, it is preferable that a plastic substrate used in
a protecting film is antistatic-treated. By subjecting the plastic
film to electrification preventing treatment, more excellent
antistatic property is obtained.
BRIEF DESCRIPTION OF THE DRAWING
[0055] FIG. 1 is a schematic construction view of an electrostatic
measuring part used for measuring a peeling electrification voltage
in Example I to Example III.
BEST MODE FOR CARRYING OUT THE INVENTION
[0056] Embodiments of the present invention will be explained in
detail below.
[0057] The pressure-sensitive adhesive composition of the present
invention is characterized in that it contains an ionic liquid, and
a (meth)acryl-based polymer containing, as a monomer component, 0.1
to 100% by weight of a (meth)acrylic acid alkylene oxide.
[0058] In addition, a pressure-sensitive adhesive composition of
the present invention is characterized in that it contains an ionic
liquid, and a polymer containing, as a monomer component, 0.5 to
30% by weight of a nitrogen-containing monomer and having a glass
transition temperature Tg of no higher than 0.degree. C.
[0059] Furthermore, the pressure-sensitive adhesive composition of
the present invention is characterized in that it contains an ionic
liquid, and a (meth)acryl-based polymer containing, as a monomer
component, 0.01 to 20% by weight of a reactive surfactant.
[0060] The ionic liquid in the present invention refers to a melt
salt (ionic compound) exhibiting the liquid state at room
temperature (25.degree. C.).
[0061] As the ionic liquid, a nitrogen-containing onium salt, a
sulfur-containing onium salt or a phosphorus-containing onium salt
is preferably used. In particular, since excellent antistatic
ability is obtained, an ionic liquid comprising an organic cation
component represented by the following general formulas (A) to (D),
and an anion component is preferably used. ##STR4## [0062] [in the
formula (A), R.sub.a represents a hydrocarbon group of a carbon
number of 4 to 20, and may contain a hetero atom, and R.sub.b and
R.sub.c are the same or different, represent hydrogen or a
hydrocarbon group of a carbon number of 1 to 16, and may contain a
hetero atom, provided that, when a nitrogen atom contains a double
bond, R.sub.c is not present] [0063] [in the formula (B), R.sub.d
represents a hydrocarbon group of a carbon number of 2 to 20, and
may contain a hetero atom, and R.sub.e, R.sub.f and R.sub.g are the
same or different, represent hydrogen or a hydrocarbon group of a
carbon number of 1 to 16, and may contain a hetero atom] [0064] [in
the formula (C), R.sub.h represents a hydrocarbon group of a carbon
number of 2 to 20, and may contain a hetero atom, and R.sub.i,
R.sub.j and R.sub.k are the same or different, represent a hydrogen
or a hydrocarbon group of a carbon number of 1 to 16, and may
contain a hetero atom] [0065] [in the formula (D), Z represents a
nitrogen atom, a sulfur atom, or a phosphorus atom, and R.sub.l,
R.sub.m, R.sub.n and R.sub.o are the same or different, represent a
hydrocarbon group of a carbon number of 1 to 20, and may contain a
hetero atom, provided that, when Z is a sulfur atom, R.sub.o is not
present]
[0066] Examples of the cation represented by the formula (A)
include a pyridinium cation, a piperidinium cation, a pyrrolidinium
cation, a cation having a pyrroline skeleton, and a cation having a
pyrrole skeleton.
[0067] Specific examples include 1-ethylpyridinium cation, a
1-butylpyridinium cation, 1-hexylpyridinium cation, a
1-butyl-3-methylpyridinium cation, a 1-butyl-4-methylpyridinium
cation, a 1-hexyl-3-methylpyridinium cation, a
1-butyl-3,4-dimethylpyridinium cation, a 1,1-dimethylpyrrolidinium
cation, a 1-ethyl-1-methylpyrrolidinium cation, a
1-methyl-1-propylpyrrolidinium cation, a 2-methyl-1-pyrroline
cation, a 1-ethyl-2-phenylindole cation, a 1,2-dimethylindole
cation, and a 1-ethylcarbazole cation.
[0068] Examples of the cation represented by the formula (B)
include an imidazolium cation, a tetrahydropyrimidinium cation, and
a dihydropyrimidinium cation.
[0069] Specific examples include a 1,3-dimethylimidazolium cation,
a 1,3-diethylimidazolium cation, a 1 -ethyl-3-methylimidazolium
cation, a 1-butyl-3-methyimidazolium cation, a
1-hexyl-3-methylimidazolium cation, 1-ocytl-3-methylimidazolium
cation, a 1-decyl-3-methylimidazolium cation, a
1-dodecyl-3-methylimidazolium cation, a
1-tetradecyl-3-methylimidazolium cation, a
1,2-dimethyl-3-propylimidazolium cation, a
1-ethyl-2,3-dimethylimidazolium cation, a
1-butyl-2,3-dimethylimidazolium cation, a
1-hexyl-2,3-dimethylimidazolium cation, a
1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium cation, a
1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium cation, a
1,2,3,4-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, a
1,2,3,5-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, a
1,3-dimethyl-1,4-dihydropyrimidinium cation, a
1,3-dimethyl-1,6-dihydropyrimidinium cation, a
1,2,3-trimethyl-1,4-dihydropyrimidinium cation, a
1,2,3-trimethyl-1,6-dihydropyrimidinium cation, a
1,2,3,4-tetramethyl-1,4-dihydropyrimidinium cation, and a
1,2,3,4-tetramethyl-1,6-dihydropyrimidinium cation.
[0070] Examples of the cation represented by the formula (C)
include a pyrazolium cation, and a pyrazolinium cation.
[0071] Specific examples include a 1-methylpyrazolium cation, a
3-methylpyrazolium cation, and a 1-ethyl-2-methylpyrazolinium
cation.
[0072] Examples of the cation represented by the formula (D)
include a tetraalkylammonium cation, a trialkylsulfonium cation, a
tetraalkylphosphonium cation, and those cations in which a part of
the alkyl group is substituted with an alkenyl group, an alkoxyl
group, or an epoxy group.
[0073] Specific examples include, for example, a tetramethyl
ammonium cation, a tetraethyl ammonium cation, a tetrapropyl
ammonium cation, a tetrabutyl ammonium cation, a tetrapentyl
ammonium cation, a tetrahexyl ammonium cation, a tetraheptyl
ammonium cation, a triethyl methyl ammonium cation, a tributyl
ethyl ammonium cation, a trimethyl decyl ammonium cation, a
trioctyl methyl ammonium cation, a tripentyl butyl ammonium cation,
a trihexyl methyl ammonium cation, a trihexyl pentyl ammonium
cation, a triheptyl methyl ammonium cation, a triheptyl hexyl
ammonium cation, an N,N-diethyl-N-methyl-N-(2-metoxyetyl) ammonium
cation, a glycidyl trimethyl ammonium cation, a diallyl dimethyl
ammonium cation, an N,N-dimethyl-N,N-dipropyl ammonium cation, an
N,N-dimethyl-N,N-dihexyl ammonium cation, an
N,N-dipropyl-N,N-dihexyl ammonium cation, an
N,N-dimethyl-N-ethyl-N-propyl ammonium cation, an
N,N-dimethyl-N-ethyl-N-butyl ammonium cation, an
N,N-dimethyl-N-ethyl-N-pentyl ammonium cation, an
N,N-dimethyl-N-ethyl-N-hexyl ammonium cation, an
N,N-dimethyl-N-ethyl-N-heptyl ammonium cation, an
N,N-dimethyl-N-propyl-N-butyl ammonium cation, an
N,N-dimethyl-N-propyl-N-pentyl ammonium cation, an
N,N-dimethyl-N-propyl-N-hexyl ammonium cation, an
N,N-dimethyl-N-propyl-N-heptyl ammonium cation, an
N,N-dimethyl-N-butyl-N-hexyl ammonium cation, an
N,N-dimethyl-N-butyl-N-heptyl ammonium cation, an
N,N-dimethyl-N-pentyl-N-hexyl ammonium cation, an
N,N-dimethyl-N-hexyl-N-heptyl ammonium cation, a trimethyl heptyl
ammonium cation, an N,N-diethyl-N-methyl-N-propyl ammonium cation,
an N,N-diethyl-N-methyl-N-pentyl ammonium cation, an
N,N-diethyl-N-methyl-N-heptyl ammonium cation, an
N,N-diethyl-N-propyl-N-pentyl ammonium cation, an triethyl methyl
ammonium cation, a triethyl propyl ammonium cation, a triethyl
pentyl ammonium cation, a triethyl heptyl ammonium cation, an
N,N-dipropyl-N-methyl-N-ethyl ammonium cation, an
N,N-dipropyl-N-methyl-N-pentyl ammonium cation, an
N,N-dipropyl-N-butyl-N-hexyl ammonium cation, an
N,N-dibutyl-N-methyl-N-pentyl ammonium cation, an
N,N-dibutyl-N-methyl-N-hexyl ammonium cation, a trioctyl methyl
ammonium cation, an N-methyl-N-ethyl-N-propyl-N-pentyl ammonium
cation, a trimethyl sulfonium cation, a triethyl sulfonium cation,
a tributyl sulfonium cation, a trihexyl sulfonium cation, a diethyl
methyl sulfonium cation, a dibutyl ethyl sulfonium cation, a
dimethyl decyl sulfonium cation, a tetramethyl phosphonium cation,
a tetraethyl phosphonium cation, a tetrabutyl phosphonium cation, a
tetrapentyl phosphonium cation, a tetrahexyl phosphonium cation, a
tetraheptyl phosphonium cation, a tetraoctyl phosphonium cation, a
triethyl methyl phosphonium cation, a tributyl ethyl phosphonium
cation, a trimethyl decyl phosphonium cation, and the like.
[0074] Among them, there are preferably used a tetra alkyl ammonium
cation, such as a triethyl methyl ammonium cation, a tributyl ethyl
ammonium cation, a trimethyl decyl ammonium cation, a trioctyl
methyl ammonium cation, a tripentyl butyl ammonium cation, a
trihexyl methyl ammonium cation, a trihexyl pentyl ammonium cation,
a triheptyl methyl ammonium cation, a triheptyl hexyl ammonium
cation, an N,N-diethyl-N-methyl-N-(2-metoxy ethyl) ammonium cation,
a glycidyl trimethyl ammonium cation, an
N,N-dimethyl-N-ethyl-N-propyl ammonium cation, an
N,N-dimethyl-N-ethyl-N-butyl ammonium cation, an
N,N-dimethyl-N-ethyl-N-pentyl ammonium cation, an
N,N-dimethyl-N-ethyl-N-hexyl ammonium cation, an
N,N-dimethyl-N-ethyl-N-heptyl ammonium cation, an
N,N-dimethyl-N-ethyl-N-nonyl ammonium cation, an
N,N-dimethyl-N-propyl-N-butyl ammonium cation, an
N,N-dimethyl-N-propyl-N-pentyl ammonium cation, an
N,N-dimethyl-N-propyl-N-hexyl ammonium cation, an
N,N-dimethyl-N-propyl-N-heptyl ammonium cation, an
N,N-dimethyl-N-butyl-N-hexyl ammonium cation, an
N,N-dimethyl-N-butyl-N-heptyl ammonium cation, an
N,N-dimethyl-N-pentyl-N-hexyl ammonium cation, an
N,N-dimethyl-N-hexyl-N-heptyl ammonium cation, an
N,N-dimethyl-N,N-dihexyl ammonium cation, a trimethyl heptyl
ammonium cation, an N,N-diethyl-N-methyl-N-propyl ammonium cation,
an N,N-diethyl-N-methyl-N-pentyl ammonium cation, an
N,N-diethyl-N-methyl-N-heptyl ammonium cation, an
N,N-diethyl-N-propyl-N-pentyl ammonium cation, a triethyl propyl
ammonium cation, a triethyl pentyl ammonium cation, a triethyl
heptyl ammonium cation, an N,N-dipropyl-N-methyl-N-ethyl ammonium
cation, an N,N-dipropyl-N-methyl-N-pentyl ammonium cation, an
N,N-dipropyl-N-butyl-N-hexyl ammonium cation, an
N,N-dipropyl-N,N-dihexyl ammonium cation, an
N,N-dibutyl-N-methyl-N-pentyl ammonium cation, an
N,N-dibutyl-N-methyl-N-hexyl ammonium cation, and an
N-methyl-N-ethyl-N-propyl-N-pentyl ammonium cation, a trialkyl
sulfonium cation, such as a trimethyl sulfonium cation, a triethyl
sulfonium cation, a tributyl sulfonium cation, a trihexyl sulfonium
cation, a diethyl methyl sulfonium cation, a dibutyl ethyl
sulfonium cation, and a dimethyl decyl sulfonium cation, a
tetraalkyl phosphonium cations, such as a tetramethyl phosphonium
cation, a tetraethyl phosphonium cation, a tetrabutyl phosphonium
cation, a tetrapentyl phosphonium cation, a tetrahexyl phosphonium
cation, a tetraheptyl phosphonium cation, a tetraoctyl phosphonium
cation, a triethyl methyl phosphonium cation, a tributyl ethyl
phosphonium cation, and a trimethyl decyl phosphonium cation.
[0075] On the other hand, the anionic component is not particularly
limited as far as it satisfies that it becomes an ionic liquid.
Specifically, for example, Cl.sup.-, Br.sup.-, I.sup.-,
AlCl.sub.4.sup.-, Al.sub.2Cl.sub.7.sup.-, BF.sub.4.sup.-,
PF.sub.6.sup.-, ClO.sub.4.sup.-, NO.sub.3.sup.-, CH.sub.3COO.sup.-,
CF.sub.3COO.sup.-, CH.sub.3SO.sub.3.sup.-, CF.sub.3SO.sub.3.sup.-,
(CF.sub.3SO.sub.2).sub.2N.sup.-, (CF.sub.3SO.sub.2).sub.3C.sup.-,
AsF.sub.6.sup.-, SbF.sub.6.sup.-, NbF.sub.6.sup.-, TaF.sub.6.sup.-,
F(HF).sub.n.sup.-, (CN).sub.2N.sup.-, C.sub.4F.sub.9SO.sub.3.sup.-,
(C.sub.2F.sub.5SO.sub.2).sub.2N.sup.-, C.sub.3F.sub.7COO.sup.-, and
(CF.sub.3SO.sub.2)(CF.sub.3CO)N.sup.- are used. Among them, in
particular, an anionic component containing a fluorine atom is
preferably used because a low melting point ionic compound is
obtained.
[0076] An embodiment of an ionic liquid used in the present
invention is used by appropriately selecting from a combination of
the aforementioned cation component and anion component.
[0077] Specific examples include, for example, 1-butyl pyridinium
tetrafluoro borate, 1-butyl pyridinium hexafluoro phosphate,
1-butyl-3-methyl pyridinium tetrafluoro borate, 1-butyl-3-methyl
pyridinium trifluoromethane sulfonate, 1-butyl-3-methyl pyridinium
bis(trifluoromethanesulfonyl) imide, 1-butyl-3-methyl pyridinium
(pentafluoro ethane sulfonyl) imide, 1-hexyl pyridinium tetrafluoro
borate, 2-methyl-1-pyrroline tetrafluoro borate, 1-ethyl-2-phenyl
indole tetrafluoro borate, 1,2-dimethyl indole tetrafluoro borate,
1-ethyl carbazole tetrafluoro borate, 1-ethyl-3-methyl imidazolium
tetrafluoro borate, 1-ethyl-3-methyl imidazolium acetate,
1-ethyl-3-methyl imidazolium trifluoro acetate, 1-ethyl-3-methyl
imidazolium heptafluoro butyrate, 1-ethyl-3-methyl imidazolium
trifluoromethane sulfonate, 1-ethyl-3-methyl imidazolium perfluoro
butane sulfonate, 1-ethyl-3-methyl imidazolium dicyanamide,
1-ethyl-3-methyl imidazolium bis(trifluoromethanesulfonyl) imide,
1-ethyl-3-methyl imidazolium bis(pentafluoro ethane sulfonyl)
imide, 1-ethyl-3-methyl imidazolium tris(trifluoromethanesulfonyl)
methyl, 1-butyl-3-methyl imidazolium tetrafluoro borate,
1-butyl-3-methyl imidazolium hexafluoro phosphate, 1-butyl-3-methyl
imidazolium trifluoro acetate, 1-butyl-3-methyl imidazolium
heptafluoro butyrate, 1-butyl-3-methyl imidazolium trifluoromethane
sulfonate, 1-butyl-3-methyl imidazolium perfluoro butane sulfonate,
1-butyl-3-methyl imidazolium bis(trifluoromethanesulfonyl) imide,
1-hexyl-3-methyl imidazolium bromide, 1-hexyl-3-methyl imidazolium
chloride, 1-hexyl-3-methyl imidazolium tetrafluoro borate,
1-hexyl-3-methyl imidazolium hexafluoro phosphate, 1-hexyl-3-methyl
imidazolium trifluoromethane sulfonate, 1-octyl-3-methyl
imidazolium tetrafluoro borate, 1-octyl-3-methyl imidazolium
hexafluoro phosphate, 1-hexyl-2,3-dimethyl imidazolium tetrafluoro
borate, 1,2-dimethyl-3-propyl imidazolium
bis(trifluoromethanesulfonyl) imide, 1-methyl pyrazolium
tetrafluoro borate, 3-methyl pyrazolium tetrafluoro borate, tetra
hexyl ammonium bis(trifluoromethanesulfonyl) imide, diallyl
dimethyl ammonium tetrafluoro borate, diallyl dimethyl ammonium
trifluoromethane sulfonate, diallyl dimethyl ammonium
bis(trifluoromethanesulfonyl) imide, diallyl dimethyl ammonium
bis(pentafluoro ethane sulfonyl) imide,
N,N-diethyl-N-methyl-N-(2-methoxy ethyl) ammonium tetrafluoro
borate, N,N-diethyl-N-methyl-N-(2-methoxy ethyl) ammonium
trifluoromethane sulfonate, N,N-diethyl-N-methyl-N-(2-methoxy
ethyl) ammonium bis(trifluoromethanesulfonyl) imide,
N,N-diethyl-N-methyl-N-(2-methoxy ethyl) ammonium bis(pentafluoro
ethane sulfonyl) imide, glycidyl trimethyl ammonium
trifluoromethane sulfonate, glycidyl trimethyl ammonium
bis(trifluoromethanesulfonyl) imide, glycidyl trimethyl ammonium
bis(pentafluoro ethane sulfonyl) imide, 1-butyl pyridinium
(trifluoromethanesulfonyl) trifluoro acetamide, 1-butyl-3-methyl
pyridinium (trifluoromethanesulfonyl) trifluoro acetamide,
1-ethyl-3-methyl imidazolium (trifluoromethanesulfonyl) trifluoro
acetamide, N,N-diethyl-N-methyl-N-(2-methoxy ethyl) ammonium
(trifluoromethane sulfonate) trifluoro acetamide, diallyl dimethyl
ammonium (trifluoromethanesulfonyl) trifluoro acetamide, glycidyl
trimethyl ammonium (trifluoromethanesulfonyl) trifluoro acetamide,
N,N-dimethyl-N-ethyl-N-propyl ammonium
bis(trifluoromethanesulfonyl) imide, N,N-dimethyl-N-ethyl-N-butyl
ammonium bis(trifluoromethanesulfonyl) imide,
N,N-dimethyl-N-ethyl-N-pentyl ammonium
bis(trifluoromethanesulfonyl) imide, N,N-dimethyl-N-ethyl-N-hexyl
ammonium bis(trifluoromethanesulfonyl) imide,
N,N-dimethyl-N-ethyl-N-heptyl ammonium
bis(trifluoromethanesulfonyl) imide, N,N-dimethyl-N-ethyl-N-nonyl
ammonium bis(trifluoromethanesulfonyl) imide,
N,N-dimethyl-N,N-dipropyl ammonium bis(trifluoromethanesulfonyl)
imide, N,N-dimethyl-N-propyl-N-butyl ammonium
bis(trifluoromethanesulfonyl) imide, N,N-dimethyl-N-propyl-N-pentyl
ammonium bis(trifluoromethanesulfonyl) imide,
N,N-dimethyl-N-propyl-N-hexyl ammonium
bis(trifluoromethanesulfonyl) imide, N,N-dimethyl-N-propyl-N-heptyl
ammonium bis(trifluoromethanesulfonyl) imide,
N,N-dimethyl-N-butyl-N-hexyl ammonium bis(trifluoromethanesulfonyl)
imide, N,N-dimethyl-N-butyl-N-heptyl ammonium
bis(trifluoromethanesulfonyl) imide, N,N-dimethyl-N-pentyl-N-hexyl
ammonium bis(trifluoromethanesulfonyl) imide,
N,N-dimethyl-N,N-dihexyl ammonium bis(trifluoromethanesulfonyl)
imide, trimethyl heptyl ammonium bis(trifluoromethanesulfonyl)
imide, N,N-diethyl-N-methyl-N-propyl ammonium
bis(trifluoromethanesulfonyl) imide, N,N-diethyl-N-methyl-N-pentyl
ammonium bis(trifluoromethanesulfonyl) imide,
N,N-diethyl-N-methyl-N-heptyl ammonium
bis(trifluoromethanesulfonyl) imide, N,N-diethyl-N-propyl-N-pentyl
ammonium bis(trifluoromethanesulfonyl) imide, triethyl propyl
ammonium bis(trifluoromethanesulfonyl) imide, triethyl pentyl
ammonium bis(trifluoromethanesulfonyl) imide, triethyl heptyl
ammonium bis(trifluoromethanesulfonyl) imide,
N,N-dipropyl-N-methyl-N-ethyl ammonium
bis(trifluoromethanesulfonyl) imide, N,N-dipropyl-N-methyl-N-pentyl
ammonium bis(trifluoromethanesulfonyl) imide,
N,N-dipropyl-N-butyl-N-hexyl ammonium bis(trifluoromethanesulfonyl)
imide, N,N-dipropyl-N,N-dihexyl ammonium
bis(trifluoromethanesulfonyl) imide, N,N-dibutyl-N-methyl-N-pentyl
ammonium bis(trifluoromethanesulfonyl) imide,
N,N-dibutyl-N-methyl-N-hexyl ammonium bis(trifluoromethanesulfonyl)
imide, trioctyl methyl ammonium bis(trifluoromethanesulfonyl)
imide, N-methyl-N-ethyl-N-propyl-N-pentyl ammonium
bis(trifluoromethanesulfonyl) imide.
[0078] As the aforementioned ionic liquid, a commercially available
ionic liquid may be used, or the liquid may be synthesized as
described below. A method of synthesizing an ionic liquid is not
particularly limited as far as an objective ionic liquid is
obtained. Generally, a halide method, a hydroxide method, an acid
ester method, a chelate forming method, and a neutralization method
described in the publication "Ionic liquid--The Front and Future of
Development--" (published by CMC) are used.
[0079] Regarding a halide method, a hydroxide method, an acid ester
method, a chelate forming method, and a neutralization method, a
synthesis method using an example of a nitrogen-containing onium
salt will be shown below, but other ionic liquid such as a
sulfur-containing onium salt, and a phosphorus-containing onium
salt can be obtained by the similar procedure.
[0080] The halide method is a method which is performed by a
reaction shown in the following formulas (1) to (3). First, a
tertiary amine and alkyl halide are reacted to obtain halide
(Reaction Equation (1), as a halogen, chlorine, bromine or iodine
is used).
[0081] The resulting halide is reacted with an acid (HA) having an
anion structure (A.sup.-) of an objective ionic liquid or a salt
(MA, M is a cation forming a salt with an objective anion such as
ammonium, lithium, sodium and potassium) of an objective ionic
liquid to obtain an objective ionic liquid (R.sub.4NA).
R.sub.3N+RX.fwdarw.R.sub.4NX (X: Cl, Br, I) (1)
R.sub.4NX+HA.fwdarw.R.sub.4NA+HX (2)
R.sub.4NX+MA.fwdarw.R.sub.4NA+MX (M: NH.sub.4, Li, Na, K, Ag etc.)
(3)
[0082] The hydroxide method is a method performed by a reaction
shown in (4) to (8). First, a halide (R.sub.4NX) is subjected to
ion exchange membrane method electrolysis (reaction equation (4)),
an OH-type ion exchange resin method (reaction equation (5)) or a
reaction with silver oxide (Ag.sub.2O) (reaction equation (6)) to
obtain a hydroxide (R.sub.4NOH) (as a halogen, chlorine, bromine or
iodine is used).
[0083] The resulting hydroxide is subjected to a reaction of
reaction equations (7) to (8) as in the aforementioned halide
method to obtain an objective ionic liquid (R.sub.4NH).
R.sub.4NX+H.sub.2O.fwdarw.R.sub.4NOH+1/2H.sub.2+1/2X.sub.2 (X: Cl,
Br, I) (4) R.sub.4NX+P--OH.fwdarw.R.sub.4NOH+P--X (P--OH: OH-type
ion exchange resin) (5)
R.sub.4NX+1/2Ag.sub.2O+1/2H.sub.2O+R.sub.4NOH+AgX (6)
R.sub.4NOH+HA.fwdarw.R.sub.4NA+H.sub.2O (7)
R.sub.4NOH+MA.fwdarw.R.sub.4NA+MOH (M: NH.sub.4, Li, Na, K, Ag
etc.) (8)
[0084] The acid ester method is a method performed by a reaction
shown in (9) to (11). First, tertiary amine (R.sub.3N) is reacted
with acid ester to obtain an acid esterified substance (reaction
equation (9), as acid ester, ester of an inorganic acid such as
sulfuric acid, sulfurous acid, phosphoric acid, phosphorous acid,
and carbonic acid, or ester of organic acid such as methanesulfonic
acid, methylphosphonic acid and formic acid is used).
[0085] The resulting acid esterified substance is subjected to a
reaction of reaction equations (10) to (11) as in the
aforementioned halide method, to obtain an objective ionic liquid
(R.sub.4NA). Alternatively, as acid ester, methyl trifluoromethane
sulfonate, or methyl trifluoroacetate may be used to directly
obtain an ionic liquid. ##STR5##
[0086] The chelate forming method is a method performed by a
reaction as shown in (12) to (15). First, halide of quaternary
ammonium (R.sub.4NX), hydroxide of quaternary ammonium
(R.sub.4NOH), or carbonic acid esterified substance of quaternary
ammonium (R.sub.4NOCO.sub.2CH.sub.3) is reacted with hydrogen
fluoride (HF) or ammonium fluoride (NH.sub.4F) to obtain a
quaternary ammonium fluoride salt (reaction equation (12) to
(14)).
[0087] The resulting quaternary ammonium fluoride salt can be
subjected to a chelate forming reaction with fluoride such as
BF.sub.3, AlF.sub.3, PF.sub.5, ASF.sub.5, SbF.sub.5, NbF.sub.5 and
TaF.sub.6, to obtain an ionic liquid (reaction equation (15)).
R.sub.4NX+HF.fwdarw.R.sub.4NF+HX (X: Cl, Br, I) (12)
R.sub.4NY+HF.fwdarw.R.sub.4NF+HY (Y: OH, OCO.sub.2CH.sub.3) (13)
R.sub.4NY+NH.sub.4F.fwdarw.R.sub.4NF+NH.sub.3+HY (Y: OH,
OCO.sub.2CH.sub.3) (14)
R.sub.4NF+MF.sub.n-1.fwdarw.R.sub.4NMF.sub.n (15) (MF.sub.n-1:
BF.sub.3, AlF.sub.3, PF.sub.5, ASF.sub.5, SbF.sub.5, NbF.sub.5,
TaF.sub.5 etc.)
[0088] The neutralization method is a method performed by a
reaction shown in (16). An ionic liquid can be obtained by reacting
tertiary amine and an organic acid such as HBF.sub.4, HPF.sub.6,
CH.sub.3COOH, CF.sub.3COOH, CF.sub.3SO.sub.3H,
(CF.sub.3SO.sub.2).sub.2NH, (CF.sub.3SO.sub.2).sub.3CH, and
(C.sub.2F.sub.5SO.sub.2).sub.2NH.
R.sub.3N+HZ.fwdarw.R.sub.3HN.sup.+Z.sup.- (16) [HZ: HBF.sub.4,
HPF.sub.6, CH.sub.3COOH, CF.sub.3COOH, CF.sub.3SO.sub.3H,
(CF.sub.3SO.sub.2).sub.2NH, (CF.sub.3SO.sub.2).sub.2NH,
(CF.sub.3SO.sub.2).sub.3CH, (C.sub.2F.sub.5SO.sub.2).sub.2NH
organic acid such as]
[0089] The aforementioned R represents hydrogen or a hydrocarbon
group of a carbon number of 1 to 20, and may contain a hetero
atom.
[0090] Since an amount of an ionic liquid to be blended varies
depending on compatibility between a polymer and an ionic liquid to
be used, the amount can not be always indiscriminately defined, but
generally is preferably 0.01 to 40 parts by weight, more preferably
0.03 to 20 parts by weight, most preferably 0.05 to 10 parts by
weight relative to 100 parts by weight of a base polymer. When the
amount is less than 0.01 part by weight, sufficient antistatic
property is not obtained and, when the amount exceeds 40 parts by
weight, there is a tendency that staining on an adherend is
increased.
[0091] The pressure-sensitive adhesive composition of the present
invention is characterized in that it contains an ionic liquid, and
a (meth)acryl-based polymer containing, as a monomer component, 0.1
to 100% by weight of a (meth)acrylic acid alkylene oxide.
[0092] In the present invention, a (meth)acryl-based polymer
containing, as a monomer component, 0.1 to 100% by weight of a
(meth)acrylic acid alkylene oxide is used as a base polymer.
[0093] The aforementioned (meth)acryl-based polymer used in the
present invention is not particularly limited as far as it is a
(meth)acryl-based polymer having pressure-sensitive adhering
property corresponding to the aforementioned property.
[0094] Examples of an oxyalkylene unit of a (meth)acrylic acid
alkylene oxide in the present invention include an alkylene group
of a carbon number of 1 to 6 such as an oxymethylene group, an
oxyethylene group, an oxypropylene group, and an oxybutylene
group.
[0095] In addition, a mole number of addition of an oxyalkylene
unit to (meth)acrylic acid is preferably 1 to 30, more preferably 1
to 20 from a viewpoint of affinity with an ionic liquid. An end of
an oxyalkylene chain may remain a hydroxyl group, or may be
substituting with other functional group, and is preferably
substituted with an alkyl group, a phenyl group, or the like for
appropriately controlling a crosslinking density.
[0096] Examples of a (meth)acrylic acid alkylene oxide in the
present invention include methoxy-polyethylene glycol(meth)acrylate
type such as methoxy-diethylene glycol (meth)acrylate, and
methoxy-triethylene glycol (meth)acrylate, ethoxy-polyethylene
glycol (meth)acrylate type such as ethoxy-diethylene glycol
(meth)acrylate, and ethoxy-triethylene glycol (meth)acrylate,
butoxy-polyethylene glycol (meth)acrylate type such as
butoxy-diethylene glycol (meth)acrylate, and butoxy-triethylene
glycol (meth)acrylate, phenoxy-polyethylene glycol (meth)acrylate
type such as phenoxy-diethylene glycol (meth)acrylate, and
phenoxy-triethylene glycol (meth)acrylate, and
methoxy-polypropylene glycol (meth)acrylate type such as
methoxy-dipropylene glycol (meth)acrylate. Among them,
ethoxy-diethylene glycol acrylate is preferably used.
[0097] (Meth)acrylic acid alkylene oxide may be used alone, or two
or more kinds may be used by mixing, and a content as a whole is
preferably 0.1 to 100% by weight, more preferably 0.3 to 90% by
weight, particularly preferably 0.5 to 80% by weight in a monomer
component of a (meth)acryl-based polymer. When a content of a
(meth)acrylic acid alkylene oxide is less than 0.1% by weight,
effect of suppressing bleeding of an ionic liquid and effect of
reducing staining of an adherend (subject to be protected) are not
sufficiently obtained, which is not preferable.
[0098] Furthermore, in the present invention, in addition to the
aforementioned (meth)acrylic acid alkylene oxide monomer component,
(meth)acryl-based monomer components having an alkyl group of a
carbon number of 1 to 14 and other polymerizable monomer components
for regulating the glass transition temperature and the peeling
properties of the (meth)acryl-based polymer can be utilized.
[0099] In the present invention, a (meth)acryl-based monomer having
an alkyl group of a carbon number of 1 to 14 can be used, and it is
more preferable to use a (meth)acryl-based monomer having an alkyl
group of a carbon number of 2 to 13. Specific examples of
(meth)acrylate having an alkyl group of a carbon number of 1 to 14
include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl
(meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate,
isobutyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl
(meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate,
n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl
(meth)acrylate, isodecyl (meth)acrylate, n-dodecyl (meth)acrylate,
n-tridecyl (meth)acrylate, and n-tetradecyl (meth)acrylate, or the
like.
[0100] Among them, n-butyl (meth)acrylate, s-butyl (meth)acrylate,
t-butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl
(meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl
(meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate,
isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl
(meth)acrylate or the like are preferable to use for the present
invention.
[0101] In the present invention, (meth)acryl-based monomers having
an alkyl group of a carbon number of 1 to 14 may be used alone, or
two or more kinds may be used by mixing, and a content as a whole
is preferably 0 to 99.9% by weight, more preferably 10 to 99.7% by
weight, particularly preferably 20 to 99.5% by weight in a monomer
component of a (meth)acryl-based polymer. By using a
(meth)acryl-based monomer having an alkyl group of a carbon number
of 1 to 14, better interaction with an ionic liquid, and better
adherability can be appropriately regulated.
[0102] As other polymerizable monomer component other than
aforementioned (meth)acryl-based monomer, a polymerizable monomer
for regulating a glass transition point or peelability of a
(meth)acryl-based polymer can be used in such a range that the
effect of the present invention is not deteriorated.
[0103] As other polymerizable monomer component, a cohesive
strength or a heat resistance improving component such as a
sulfonic acid group-containing monomer, a phosphoric acid
group-containing monomer, a cyano group-containing monomer, vinyl
esters, and an aromatic vinyl compound, and a component having a
functional group working for improving an adhering force or for a
crosslinking point, such as a carboxyl group-containing monomer, an
acid anhydride group-containing monomer, a hydroxyl
group-containing monomer, an amido group-containing monomer, an
amino group-containing monomer, an imido group-containing monomer,
an epoxy group-containing monomer, vinyl ethers can be
appropriately used. Other components may be used alone, or two or
more of them may be used by mixing.
[0104] Here, when (meth)acrylate having an acid functional group
such as a carboxyl group, a sulfonic acid group, and a phosphoric
acid group is used, it is preferable to adjust an acid value of a
(meth)acryl-based polymer 29 or less. When an acid value of a
(meth)acryl-based polymer exceeds 29, there is a tendency that
antistatic property is deteriorated.
[0105] An acid value can be adjusted by an amount of (meth)acrylate
having an acid functional group to be blended, and examples thereof
include a (meth)acryl-based polymer obtained by copolymerizing
2-ethylhexyl acrylate as a (meth)acryl-based polymer having a
carboxyl group, and acrylic acid. In this case, by adjusting
acrylic acid at 3.7 parts by weight relative to a total of 100
parts by weight of 2-ethylhexyl acrylate and acrylic acid, the
aforementioned acid value can be satisfied.
[0106] Examples of the sulfonic acid group-containing monomer
include styrenesulfonic acid, allylsulfonic acid,
2-(meth)acrylamido-2-methylpropanesulfonic acid,
(meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate,
(meth)acryloyloxynaphthalenesulfonic acid, and sodium
vinylsulfonate.
[0107] Examples of the phosphoric acid group-containing monomer
include 2-hydroxyethylacryloyl phosphate.
[0108] Examples of the cyano group-containing monomer include
acrylonitrile and methacrylonitrile.
[0109] Examples of vinylesters include vinyl acetate, vinyl
propionate, and vinyl laurate.
[0110] Examples of the aromatic vinyl compound include styrene,
chlorostyrene, chloromethylstyrene, .alpha.-methylstyrene, and
other substituted styrene.
[0111] Examples of the carboxyl group-containing monomer include
(meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl
(meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic
acid, and isocrotonic acid.
[0112] Examples of the acid anhydride group-containing monomer
include maleic acid anhydride, itaconic acid anhydride, and an acid
anhydride of the aforementioned carboxyl group-containing
monomer.
[0113] Examples of the hydroxyl group-containing monomer include
2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate,
4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate,
8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate,
12-hydroxylauryl (meth)acrylate, (4-hydroxymethylcyclohexyl)methyl
acrylate, N-methylol (meth)acrylamide, vinyl alcohol, allyl
alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutylvinyl ether, and
diethylene glycol monovinyl ether.
[0114] Examples of the amido group-containing monomer include
acrylamide, methacrylamide, diethylacrylamide, N-vinylpyrrolidone,
N,N-dimethylacrylamide, N,N-dimethylmethacrylamide,
N,N-diethylacrylamide, N,N-diethylmethacrylamide,
N,N'-methylenebisacrylamide, N,N-dimethylaminopropylacrylamide,
N,N-dimethylaminopropylmethacrylamide, and diacetoneacrylamide.
[0115] Examples of the amino group-containing monomer include
aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate,
N,N-dimethylaminopropyl (meth)acrylate, and
(meth)acryloylmorpholine.
[0116] Examples of the imido group-containing monomer include
cyclohexylmaleimide, isopropylmaleimide, N-cyclohexylmaleimide, and
itaconeimide.
[0117] Examples of the epoxy group-containing monomer include
glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, and allyl
glycidyl ether.
[0118] Examples of vinyl ethers include methyl vinyl ether, ethyl
vinyl ether, and isobutyl vinyl ether.
[0119] The aforementioned other polymerizable monomer component may
be used alone, or two or more kinds may be used by mixing, and a
content as a whole is such that a polymerizable monomer component
is preferably 0 to 85 parts by weight, more preferably 1 to 80
parts by weight, particularly preferably 2 to 75 parts by weight
relative to 100 parts by weight of a total constituting unit of a
(meth)acryl-based polymer. By using the aforementioned other
polymerizable monomer component, better interaction with an ionic
liquid, and better adherability can be appropriately regulated.
[0120] The aforementioned (meth)acryl-based polymer used in the
present invention has a weight average molecular weight of
preferably 100,000 to 5,000,000, more preferably 200,000 to
4,000,000, further preferably 300,000 to 3,000,000. When a weight
average molecular weight is less than 100,000, there is a tendency
that paste (adhesive residue) remaining is generated due to
reduction in a cohesive strength of a pressure-sensitive adhesive
composition. On the other hand, when a weight average molecular
weight exceeds 5,000,000, there is a tendency that fluidity of a
polymer is reduced, wetting on a polarizing plate becomes
insufficient, and there is a tendency that this is a cause for
peeling off which is generated between a polarizing plate and a
pressure-sensitive adhesive composition layer of a surface
protecting film. A weight average molecular weight is obtained by
measurement with GPC (gel permeation chromatography).
[0121] In addition, the aforementioned (meth)acryl-based polymer of
which the glass transition temperature (Tg) of is no lower than
-100.degree. C. is generally used, and it is preferable for the
glass transition temperature to be -90.degree. C. to 0.degree. C.,
and it is more preferable for it to be -80.degree. C. to
-10.degree. C. When a glass transition temperature is higher than
0.degree. C., it becomes difficult to obtain a sufficient adhering
property and tends to be a cause for peeling off which is generated
between a polarizing plate and a pressure-sensitive adhesive
composition layer of a pressure-sensitive adhesive sheet.
Furthermore, a glass transition temperature (Tg) of a
(meth)acryl-based polymer can be adjusted in the aforementioned
range by appropriating changing a monomer component and a
composition ratio to be used.
[0122] In addition, a pressure-sensitive adhesive composition of
the present invention is characterized in that it contains an ionic
liquid, and a polymer containing, as a monomer component, 0.5 to
30% by weight of a nitrogen-containing monomer and having a glass
transition temperature Tg of no higher than 0.degree. C.
[0123] In the present invention, a (meth)acryl-based polymer
containing, as a monomer component, 0.5 to 30% by weight of a
nitrogen-containing monomer and having a glass transition
temperature Tg of no higher than 0.degree. C. is used as a base
polymer.
[0124] The aforementioned (meth)acryl-based polymer used in the
present invention is not particularly limited as far as it is a
(meth)acryl-based polymer having pressure-sensitive adhering
property corresponding to the aforementioned property.
[0125] Specific examples of a nitrogen-containing monomer in the
present invention include, for example, an amino group containing
monomer, an imide group containing monomer, a cyano group
containing monomer, acryloylmorpholine, and the like.
[0126] Examples of the amido group-containing monomer include
acrylamide, methacrylamide, diethylacrylamide, N-vinylpyrrolidone,
N,N-dimethylacrylamide, N,N-dimethylmethacrylamide,
N,N-diethylacrylamide, N,N-diethylmethacrylamide,
N,N'-methylenebisacrylamide, N,N-dimethylaminopropylacrylamide,
N,N-dimethylaminopropylmethacrylamide, and diacetoneacrylamide.
[0127] Examples of the amino group-containing monomer include
aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate,
N,N-dimethylaminopropyl (meth)acrylate, and
(meth)acryloylmorpholine.
[0128] Examples of the imido group-containing monomer include
cyclohexylmaleimide, isopropylmaleimide, N-cyclohexylmaleimide, and
itaconeimide.
[0129] Examples of the cyano group-containing monomer include
acrylonitrile and methacrylonitrile.
[0130] A nitrogen-containing monomer may be used alone, or two or
more of them may be used by mixing, and it is preferable for the
amount of nitrogen-containing monomer to be 0.5% to 30% by weight
in the monomer component of the aforementioned polymer, 1% to 25%
by weight is more preferable, and 2% to 20% by weight is
particularly preferable. In the case where the content of
nitrogen-containing monomer is lower than 0.5% by weight, bleeding
restricting effects of the ionic liquid and staining reducing
effects on the adherend sometimes fail to be sufficiently gained,
which is not preferable. On the other hand, in the case where the
content of nitrogen-containing monomer is greater than 30% by
weight, the adhesive strength of the pressure-sensitive adhesive
composition becomes too high, which sometimes causes damage to the
adherend, particularly when applied as a surface protecting film,
which is not preferable.
[0131] In addition, the aforementioned polymer of which the glass
transition temperature (Tg) is no higher than 0.degree. C. is
generally used as the base polymer, and it is preferable for the
glass transition temperature to be -100.degree. C. to -5.degree.
C., and it is more preferable for it to be -80.degree. C. to
-10.degree. C. In the case where the glass transition temperature
is higher than 0.degree. C., sometimes it becomes difficult to
obtain sufficient adhesive strength. Here, the glass transition
temperature (Tg) of the base polymer can be regulated within the
aforementioned range by appropriately changing the monomer
components that are used and the composition ratio thereof.
[0132] As these polymers, polymers which are generally used as a
polymer in pressure-sensitive adhesive compositions are cited, such
as (meth)acryl-based polymers comprising one or more kinds of
(meth)acrylate having an alkyl group of a carbon number of 1 to 14
as the main component, natural rubbers, styrene-isoprene-styrene
block copolymers (SIS block copolymers), styrene-butadiene-styrene
block copolymers (SBS block copolymers),
styrene-ethylene.cndot.butylene-styrene block copolymers (SEBS
block copolymers), styrene-butadiene rubbers, polybutadiene,
polyisoprene, polyisobutylene, butyl rubbers, chloroprene rubbers,
silicone rubbers, or the like.
[0133] Among them, the (meth)acryl-based polymers comprising one or
more kinds of (meth)acrylate having an alkyl group of a carbon
number of 1 to 14 as the main component are preferably used, since
a high compatibility with an ionic liquid and excellent adhesive
properties can be gained.
[0134] As for the (meth)acryl-based polymer comprising one or more
kinds of (meth)acrylate having an alkyl group of a carbon number of
1 to 14 as the main component, a (meth)acryl-based polymer
comprising 50% to 99.5% by weight of one or more kinds of
(meth)acrylate having an alkyl group of a carbon number of 1 to 14
as the main component can be cited as a preferable example.
[0135] Examples of (meth)acrylate having an alkyl group of a carbon
number of 1 to 14 include methyl (meth)acrylate, ethyl
(meth)acrylate, n-butyl (meth)acrylate, s-butyl (meth)acrylate,
t-butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl
(meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl
(meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate,
isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl
(meth)acrylate, n-dodecyl (meth)acrylate, n-tridecyl
(meth)acrylate, and n-tetradecyl (meth)acrylate.
[0136] Among them, when used in the surface protecting film of the
present invention, (meth)acrylate having an alkyl group of a carbon
number of 6 to 14 such as hexyl(meth)acrylate, 2-ethylhexyl
(meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate,
n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl
(meth)acrylate, isodecyl (meth)acrylate, n-dodecyl (meth)acrylate,
n-tridecyl (meth)acrylate, and n-tetradecyl (meth)acrylate is
suitably used. By using a (meth)acryl-based polymer consisting of
(meth)acrylate having an alkyl group of a carbon number of 6 to 14,
it becomes easy to control an adhesive strength to an adherend low,
and excellent re-peelability is obtained.
[0137] In addition, as for other polymerizable monomer components,
a polymerizable monomer for regulating the glass transition
temperature and the peeling properties of the (meth)acryl-based
polymer can be utilized so that Tg becomes no higher than 0.degree.
C. (conventionally, -100.degree. C. or higher), since it becomes
easy to maintain adhesive performance, as long as the effects of
the present invention are not lost.
[0138] As other polymerizable monomer component, a cohesive
strength or a heat resistance improving component such as a
sulfonic acid group-containing monomer, a phosphoric acid
group-containing monomer, vinyl esters, and an aromatic vinyl
compound, and a component having a functional group working for
improving an adhering force or for a crosslinking point, such as a
carboxyl group-containing monomer, an acid anhydride
group-containing monomer, a hydroxyl group-containing monomer, an
epoxy group-containing monomer, vinyl ethers can be appropriately
used. Other components may be used alone, or two or more of them
may be used by mixing.
[0139] Here, when (meth)acrylate having an acid functional group
such as a carboxyl group, a sulfonic acid group, and a phosphoric
acid group is used, it is preferable to adjust an acid value of a
(meth)acryl-based polymer 29 or less. When an acid value of a
(meth)acryl-based polymer exceeds 29, there is a tendency that
antistatic property is deteriorated. Furthermore, in the case where
the material is applied to a surface protecting film, it is
preferable to adjust the acid value of the (meth)acryl-based
polymer to 1 or less. In the case where the acid value of the
(meth)acryl-based polymer exceeds 1, the adhesive strength tends to
increase with time.
[0140] As specific examples of the aforementioned other
polymerizable monomer components, the previously illustrated
examples of the present specification can be cited.
[0141] The aforementioned other polymerizable monomer components
may be used alone, or two or more kinds may be used by mixing, and
a content as a whole is such that a polymerizable monomer component
is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10
parts by weight of a total constituting unit of a (meth)acryl-based
polymer. By using the aforementioned other polymerizable monomer
component, better interaction with an ionic liquid, and better
adherability can be appropriately regulated.
[0142] The aforementioned (meth)acryl-based polymer used in the
present invention has a weight average molecular weight of
preferably 100,000 to 5,000,000, more preferably 200,000 to
4,000,000, further preferably 300,000 to 3,000,000. When a weight
average molecular weight is less than 100,000, there is a tendency
that paste (adhesive residue) remaining is generated due to
reduction in a cohesive strength of a pressure-sensitive adhesive
composition. On the other hand, when a weight average molecular
weight exceeds 5,000,000, there is a tendency that fluidity of a
polymer is reduced, wetting on a polarizing plate becomes
insufficient, and there is a tendency that this is a cause for
peeling off which is generated between a polarizing plate and a
pressure-sensitive adhesive composition layer of a surface
protecting film. A weight average molecular weight is obtained by
measurement with GPC (gel permeation chromatography).
[0143] Furthermore, a pressure-sensitive adhesive composition of
the present invention is characterized in that it contains an ionic
liquid, and a (meth)acryl-based polymer containing, as a monomer
component, 0.01 to 20% by weight of a reactive surfactant.
[0144] In the present invention, the (meth)acryl-based polymer
containing, as a monomer component, 0.01 to 20% by weight of a
reactive surfactant is used as a base polymer.
[0145] The aforementioned (meth)acryl-based polymer used in the
present invention is not particularly limited as far as it is a
(meth)acryl-based polymer having pressure-sensitive adhering
property corresponding to the aforementioned property.
[0146] A reactive surfactant in the present invention refers to a
reactive surfactant having a reactive unsaturated bond. Specific
examples thereof include, for example, an anion type reactive
surfactant, a nonion type reactive surfactant, and a cation type
reactive surfactant, having an acryloyl group, a methacryloyl
group, or an allyl group. Among them, an anion type reactive
surfactant, a nonion type reactive surfactant, and a cation type
reactive surfactant, which have an acryloyl group, a methacryloyl
group, or an ally group with an ethylene oxide group, are
preferably used.
[0147] The anion type reactive surfactants, represented by the
formulas (A1) to (A16), are cited as examples. ##STR6##
[0148] [In the formula (A1), R.sub.1 represents a hydrogen or a
methyl group, R.sub.2 represents a hydrocarbon group or an acyl
group of a carbon number of 1 to 30, M represents an alkali metal,
an alkaline-earth metal, an ammonium group, or a hydroxyalkyl
ammonium group of a carbon number of 1 to 4, R.sub.3 and R.sub.4
are the same or different and each is an alkylene group of a carbon
number of 1 to 6, n is an integer from 0 to 50, and m is an integer
from 0 to 20.] ##STR7##
[0149] [In the formula (A2), R.sub.1 represents a hydrogen or a
methyl group, R.sub.2 represents a hydrocarbon group or an acyl
group of a carbon number of 1 to 30, R.sub.3 and R.sub.4 are the
same or different and each is an alkylene group of a carbon number
of 1 to 6, M.sub.1 and M.sub.2 are the same or different and each
is an alkali metal, an alkaline-earth metal, an ammonium group, or
a hydroxyalkyl ammonium group of a carbon number of 1 to 4, n is an
integer from 0 to 50, and m is an integer from 0 to 20.]
##STR8##
[0150] [In the formula (A3), R.sub.1 and R.sub.2 represent hydrogen
or methyl groups, R.sub.3 represents an alkyl group or an alkenyl
group of a carbon number of 1 to 20, M represents an alkali metal,
an alkaline-earth metal, or an ammonium group.] ##STR9##
[0151] [In the formula (A4), R.sub.1 represents a hydrogen or a
methyl group, R.sub.2 and R.sub.7 are the same or different and
each is an alkylene group of a carbon number of 1 to 6, R.sub.3 and
R.sub.5 are the same or different and each is a hydrogen or alkyl
group, R.sub.4 and R.sub.6 are the same or different and each is a
hydrogen, an alkyl group, a benzyl group, or a styrene group, M
represents an alkali metal, an alkali-earth metal or an ammonium
group, and n and m represent integers from 1 to 50.] ##STR10##
[0152] [In the formula (A5), R.sub.1 represents a hydrogen or a
methyl group, R.sub.2 represents an alkylene group of a carbon
number of 1 to 6, M represents an alkali metal, an alkaline-earth
metal, or an ammonium group, and n represents an integer from 2 to
50.] ##STR11##
[0153] [In the formula (A6), R.sub.1 represents a hydrogen or a
methyl group, R.sub.2 represents a hydrocarbon group or an acyl
group of a carbon number of 1 to 30, R.sub.3 and R.sub.4 are the
same or different and each is an alkylene group of a carbon number
of 1 to 6, M represents an alkali metal, an alkaline-earth metal,
an ammonium group, or a hydroxalkyl ammonium group of a carbon
number of 1 to 4, n represents an integer from 0 to 50, and m
represents an integer from 0 to 20.] ##STR12##
[0154] [In the formula (A7), R.sub.1 represents a hydrogen or a
methyl group, R.sub.2 represents a hydrocarbon group or an acyl
group of a carbon number of 1 to 30, R.sub.3 and R.sub.4 are the
same or different and each is an alkylene group of a carbon number
of 1 to 6, M.sub.1 and M.sub.2 are the same or different and each
is an alkali metal, an alkaline-earth metal, an ammonium group, or
a hydroxyalkyl ammonium group of a carbon number of 1 to 4, n
represents an integer from 0 to 50, and m represents an integer
from 0 to 20.] ##STR13##
[0155] [In the formula (A8), R represents a hydrocarbon group of a
carbon number of 1 to 30 or an oxyalkylene group of a carbon number
of 1 to 6.] ##STR14##
[0156] [In the formula (A9), R.sub.1 represents a hydrocarbon
group, an amino group, or a carboxylic acid residue, R.sub.2
represents an alkylene group of a carbon number of 1 to 6, and n
represents an integer from 0 to 50.] ##STR15##
[0157] [In the formula (A10), R.sub.1 represents a hydrocarbon
group of a carbon number of 1 to 30, R.sub.2 represents a hydrogen
or a hydrocarbon group of a carbon number of 1 to 30, R.sub.3
represents a hydrogen or a propenyl group, R.sub.4 represents an
alkylene group of a carbon number of 1 to 6, M represents an alkali
metal, an alkaline-earth metal, an ammonium group, or an
alkanolamine residue, and n represents an integer from 1 to 50.]
##STR16##
[0158] [In the formula (A11), R.sub.1 represents a hydrogen or a
methyl group, R.sub.2 and R.sub.4 are the same or different and
each is an alkylene groups of a carbon number of 1 to 6, R.sub.3
represents a hydrocarbon group of a carbon number of 1 to 30, M
represents a hydrogen, an alkali metal, an alkaline-earth metal, an
ammonium group, or an alkanolammonium group, and n and m represent
integers from 1 to 50.] ##STR17##
[0159] [In the formula (A12), R.sub.1 and R.sub.5 are the same or
different and each is a hydrogen or a methyl group, R.sub.2 and
R.sub.4 are the same or different and each is an alkylene group of
a carbon number of 1 to 6, R.sub.3 represents a hydrocarbon group
of a carbon number of 1 to 30, M represents a hydrogen, an alkali
metal, an alkaline-earth metal, an ammonium group, or an
alkanolammonium group, and n and m represent integers from 1 to
50.] ##STR18##
[0160] [In the formula (A13), R represents a hydrocarbon group of a
carbon number of 1 to 30, M is an alkali metal, an alkaline-earth
metal, or an ammonium group.] MOOCCH.dbd.CHCOOR.sub.1O.sub.nR.sub.2
(A 14)
[0161] [In the formula (A14), R.sub.1 represents an alkylene group
of a carbon number of 1 to 6, R.sub.2 represents a hydrocarbon
group of a carbon number of 1 to 30, M represents a hydrogen, an
alkali metal, an alkaline-earth metal, an ammonium group, or an
amine group, and n represents an integer from 1 to 50.]
##STR19##
[0162] [In the formula (A15), R represents a hydrocarbon group of a
carbon number of 1 to 30, M represents a hydrogen, an alkali metal,
an alkaline-earth metal, or an ammonium group, n represents an
integer 1 or 2, an m represents an integer from 2 to 4.]
##STR20##
[0163] [In the formula (A16), R.sub.1 represents a hydrocarbon
group of a carbon number of 1 to 30, and M represents a hydrogen,
an alkali metal, an alkaline-earth metal, or an ammonium
group.]
[0164] Nonion type reactive surfactants, represented by the
formulas (N1) to (N5), can be cited as examples. ##STR21##
[0165] [In the formula (N1), R.sub.1 represents a hydrogen or a
methyl group, R.sub.2 represents a hydrocarbon group or an acyl
group of a carbon number of 1 to 30, R.sub.3 and R.sub.4 represent
the same or different and each is an alkylene group of a carbon
number of 1 to 6, and n and m represent integers from 0 to 50.]
##STR22##
[0166] [In the formula (N2), R.sub.1 represents a hydrogen or a
methyl group, R.sub.2, R.sub.3 and R.sub.4 are the same or
different and each is an alkylene group of a carbon number of 1 to
6, n, m and l are integers from 0 to 50 satisfying n+m+l is 1 to
50.] ##STR23##
[0167] [In the formula (N3), R.sub.1 represents a hydrogen or a
methyl group, R.sub.2 and R.sub.3 are the same or different and
each is an alkylene group of a carbon number of 1 to 6, R.sub.4
represents a hydrocarbon group or an acyl group of a carbon number
of 1 to 30, and n and m represent integers from 0 to 50.]
##STR24##
[0168] [In the formula (N4), R.sub.1 and R.sub.2 are the same or
different and each is a hydrocarbon group of a carbon number of 1
to 30, R.sub.3 represents a hydrogen or a propenyl group, R.sub.4
represents an alkylene group of a carbon number of 1 to 6, and n
represents an integer from 1 to 50.] ##STR25##
[0169] [In the formula (N5), R.sub.1 and R.sub.3 are the same or
different and each is an alkylene group of a carbon number of 1 to
6, R.sub.2 and R.sub.4 are the same or different and each is a
hydrogen, hydrocarbon group, or acyl group of a carbon number of 1
to 30, and n and m are integers from 0 to 50 satisfying n+m is 3 to
50.]
[0170] Cation type reactive surfactants, represented by the
formulas (C1) and (C2), can be cited as examples. ##STR26##
[0171] [In the formula (C1), R.sub.1 and R.sub.2 are the same or
different and each is an alkyl group of a carbon number of 1 to 30,
R.sub.3 represents a hydrocarbon group of a carbon number of 1 to
30, and X represents a chlorine or a bromine.] ##STR27##
[0172] [In the formula (C2), R represents a hydrocarbon group of a
carbon number of 1 to 30, which may include a hetero atom.]
[0173] The reactive surfactants may be used alone, or two or more
of them may be used by mixing, and it is preferable for the amount
to be 0.01% to 20% by weight in the monomer components of the
(meth)acryl-based polymer, more preferably from 0.05% to 10% by
weight, particularly preferably from 0.1% to 5% by weight. In the
case where the content of the reactive surfactant is lower than
0.01% by weight, bleeding restricting effects of the ionic liquid
and staining reducing effects on the adherend sometimes fail to be
sufficiently gained, which is not preferable. On the other hand, in
the case where the content is greater than 20% by weight, the
staining can occur on the adherend, which is not preferable.
[0174] In addition, as other polymerizable monomer component other
than aforementioned reactive surfactant, a polymerizable monomer
such as a (meth)acrylate having an alkyl group of a carbon number
of 1 to 14 for regulating a glass transition point or peelability
of a (meth)acryl-based polymer can be used in such a range that the
effect of the present invention is not deteriorated.
[0175] In the present invention, a (meth)acryl-based monomer having
an alkyl group of a carbon number of 1 to 14 can be used, and it is
more preferable to use a (meth)acryl-based monomer having an alkyl
group of a carbon number of 2 to 13.
[0176] Specific examples of (meth)acrylate having an alkyl group of
a carbon number of 1 to 14 include methyl (meth)acrylate, ethyl
(meth)acrylate, n-butyl (meth)acrylate, s-butyl (meth)acrylate,
t-butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl
(meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl
(meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate,
isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl
(meth)acrylate, n-dodecyl (meth)acrylate, n-tridecyl
(meth)acrylate, and n-tetradecyl (meth)acrylate or the like.
[0177] Among them, n-butyl (meth)acrylate, s-butyl (meth)acrylate,
t-butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl
(meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl
(meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate,
isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl
(meth)acrylate or the like are preferable to use for the present
invention.
[0178] In the present invention, (meth)acryl-based monomers having
an alkyl group of a carbon number of 1 to 14 may be used alone, or
two or more kinds may be used by mixing, and a content as a whole
is preferably 50 to 99.9% by weight, more preferably 60 to 99% by
weight, particularly preferably 70 to 95% by weight in a monomer
component of a (meth)acryl-based polymer. By using a
(meth)acryl-based monomer having an alkyl group of a carbon number
of 1 to 14, better interaction with an ionic liquid, and better
adherability can be appropriately regulated.
[0179] In addition, as other polymerizable monomer component other
than aforementioned (meth)acryl-based monomer, a polymerizable
monomer for regulating a glass transition point or peelability of a
(meth)acryl-based polymer can be used in such a range that the
effect of the present invention is not deteriorated.
[0180] As other polymerizable monomer component, a cohesive
strength or a heat resistance improving component such as a
sulfonic acid group-containing monomer, a phosphoric acid
group-containing monomer, a cyano group-containing monomer, vinyl
esters, and an aromatic vinyl compound, and a component having a
functional group working for improving an adhering force or for a
crosslinking point, such as a carboxyl group-containing monomer, an
acid anhydride group-containing monomer, a hydroxyl
group-containing monomer, an amido group-containing monomer, an
amino group-containing monomer, an imido group-containing monomer,
an epoxy group-containing monomer, vinyl ethers can be
appropriately used. Other components may be used alone, or two or
more of them may be used by mixing.
[0181] Here, when (meth)acrylate having an acid functional group
such as a carboxyl group, a sulfonic acid group, and a phosphoric
acid group is used, it is preferable to adjust an acid value of a
(meth)acryl-based polymer 29 or less. When an acid value of a
(meth)acryl-based polymer exceeds 29, there is a tendency that
antistatic property is deteriorated. Furthermore, in the case where
the material is applied to a surface protecting film, it is
preferable to adjust the acid value of the (meth)acryl-based
polymer to 1 or less. In the case where the acid value of the
(meth)acryl-based polymer exceeds 1, the adhesive strength tends to
increase with time.
[0182] As specific examples of the aforementioned other
polymerizable monomer components, the previously illustrated
examples of the present specification can be cited.
[0183] In the present invention, the aforementioned other
polymerizable monomer may be used alone, or two or more kinds may
be used by mixing, and a content as a whole is preferably 0 to
49.99% by weight, more preferably 0.5 to 40% by weight,
particularly preferably 1 to 20% by weight in a monomer component
of a (meth)acryl-based polymer. By using the aforementioned other
polymerizable monomer, better interaction with an ionic liquid, and
better adherability can be appropriately regulated.
[0184] The aforementioned (meth)acryl-based polymer used in the
present invention has a weight average molecular weight of
preferably 100,000 to 5,000,000, more preferably 200,000 to
4,000,000, further preferably 300,000 to 3,000,000. When a weight
average molecular weight is less than 100,000, there is a tendency
that paste (adhesive residue) remaining is generated due to
reduction in a cohesive strength of a pressure-sensitive adhesive
composition. On the other hand, when a weight average molecular
weight exceeds 5,000,000, there is a tendency that fluidity of a
polymer is reduced, wetting on a polarizing plate becomes
insufficient, and there is a tendency that this is a cause for
peeling off which is generated between a polarizing plate and a
pressure-sensitive adhesive composition layer of a surface
protecting film. A weight average molecular weight is obtained by
measurement with GPC (gel permeation chromatography).
[0185] In addition, the aforementioned (meth)acryl-based polymer of
which the glass transition temperature (Tg) of is no lower than
-100.degree. C. is generally used, and it is preferable for the
glass transition temperature to be -90.degree. C. to 0.degree. C.,
and it is more preferable for it to be -80.degree. C. to
-10.degree. C. When a glass transition temperature is higher than
0.degree. C., there is a tendency that fluidity of a polymer is
reduced, wetting on a polarizing plate becomes insufficient, and
there is a tendency that this is a cause for peeling off which is
generated between a polarizing plate and a pressure-sensitive
adhesive composition layer of a surface protecting film. Here, a
glass transition temperature (Tg) of a (meth)acryl-based polymer
can be adjusted in the aforementioned range by appropriating
changing a monomer component and a composition ratio to be
used.
[0186] The aforementioned (meth)acryl-based polymer of the present
invention is obtained by a polymerization method which is generally
used as a procedure for synthesizing a (meth)acryl-based polymer
such as solution polymerization, emulsion polymerization, bulk
polymerization and suspension polymerization. In addition, the
resulting polymer may be any of a random copolymer, a block
copolymer, and a graft copolymer.
[0187] In the present invention, an ethylene oxide group-containing
compound may be blended, if necessary. In particular, the ethylene
oxide group-containing compound is preferably used when a
(meth)acryl-based polymer containing, as a monomer component, 0.1
to 100% by weight of a (meth)acrylic acid alkylene oxide is
preferably used as the base polymer.
[0188] The ethylene oxide group-containing compound in the present
invention is not particularly limited, as long as it is a compound
that has an ethylene oxide group, and surfactants that have an
ethylene oxide group, ethylene oxide group-containing polyether
based polymers, ethylene glycol group-containing (meth)acryl-based
polymers, and the like can be cited as examples. In particular,
surfactants having an ethylene oxide group provide well-balanced
compatibility between the base polymer and the ionic liquid, and
thus are preferably used.
[0189] Examples of the surfactants having an ethylene oxide group
include, for example, nonionic surfactants, such as polyoxyethylene
fatty acid esters, polyoxyethylene sorbitan fatty acid esters,
polyoxyethylene sorbitol fatty acid esters, polyoxyethylene alkyl
ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene alkyl
phenyl ethers, polyoxyethylene derivatives, polyoxyethylene alkyl
amines, and polyoxyethylene alkyl amine fatty acid esters, anionic
surfactants, such as polyoxyethylene alkyl ether sulfates,
polyoxyethylene alkyl ether phosphates and polyoxyethylene alkyl
phenyl ether phosphates, and cationic surfactants, as well as
cationic and anionic surfactants that include an ethylene oxide
group. In addition, the surfactants may have a reactive
substituent, such as (meth)acryloyl group or allyl group.
[0190] It is preferable for the number of moles of oxyethylene
units added in the surfactant having ethylene oxide group as
described above to be 1 to 50 from the point of view of
interactions with the ionic liquid, and 2 to 40 is more preferable.
In the case where the surfactant does not have an ethylene oxide
group, it is difficult to provide a well balanced compatibility
between the ionic liquid and the base polymer, which is not
preferable since bleeding to the adherend tends to increase. On the
other hand, in the case where a surfactant is used of which the
number of moles of the added oxyethylene units exceeds 50, the
ionic liquid is strongly coordinated by the ethylene oxide groups,
so that the antistaticity tends to be lowered.
[0191] Examples of an ethylene oxide group-containing
polyether-based polymer include a random copolymer and a block
copolymer of polyethylene glycol and polypropylene glycol such as a
block copolymer of polypropylene glycol-polyethylene
glycol-polypropyelene golycol, a block copolymer of polypropylene
glycol-polyethylene glycol, a block copolymer of polyethylene
glycol-polypropylene glycol-polyethylene glycol, and a random
copolymer of polypropylene glycol-polyethylene glycol. A terminus
of a glycol chain may remain a hydroxyl group, or may be
substituted with an alkyl group or a phenyl group.
[0192] A ratio of polyethylene glycol of these random copolymers
and these block copolymers of polyethylene glycol and polypropylene
glycol, 5 to 74% by weight is preferable, 10 to 70% by weight is
more preferable. When a ratio of polyethylene glycol is less than
5% by weight, compatibility with an ionic liquid becomes worse, and
there is a tendency that sufficient antistatic is hardly obtained
and, when the ratio is 75% by weight or more, crystallizability
becomes high, compatibility with an acryl-based polymer becomes
worse, and there is a tendency that sufficient antistatic is hardly
obtained.
[0193] As an ethylene glycol group-containing acryl-based polymer,
an acryl-based polymer having ethylene glycol group-containing
(meth)acrylate as an essential component is used.
[0194] As an addition mole number of an oxyethylene unit to
(meth)acrylate, 1 to 30 is preferable, and 2 to 20 is more
preferable from a viewpoint of coordination of an ionic liquid. A
terminus of an ethylene oxide chain may remain a hydroxyl group,
and may be substituted with an alkyl group or a phenyl group.
[0195] Specific examples of ethylene glycol group-containing
(meth)acrylate include methoxy-polyethylene glycol (meth)acrylate
type such as methoxy-diethylene glycol (meth)acrylate, and
methoxy-triethylene glycol (meth)acrylate, ethoxy-polyethylene
glycol (meth)acrylate type such as ethoxy-diethylene glycol
(meth)acrylate, and ethoxy-triethylene glycol (meth)acrylate,
butoxy-polyethylene glycol (meth)acrylate type such as
butoxy-diethylene glycol (meth)acrylate, and
butoxy-triethylene-glycol (meth)acrylate, phenoxy-polyethylene
glycol (meth)acrylate type such as phenoxy-diethylene glycol
(meth)acrylate, and phenoxy-triethylene glycol (meth)acrylate,
2-ethylhexyl-polyethylene glycol (meth)acrylate, and
nonylphenol-polyethylene glycol (meth)acrylate type.
[0196] In addition, as a monomer component other than the
aforementioned components, acrylate and/or methacrylate having an
alkyl group of a carbon number of 1 to 14 such as methyl
(meth)acrylate, ethyl(meth)acrylate, n-butyl (meth)acrylate,
t-butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl
(meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl
(meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate,
isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl
(meth)acryalte, n-dodecyl(meth)acrylate, n-tridecyl (meth)acrylate,
and n-tetradecyl (meth)acrylate can be also used.
[0197] Further, carboxyl group-containing (meth)acrylate,
phosphoric acid group-containing (meth)acrylate, cyano
group-containing (meth)acrylate, vinyl esters, aromatic vinyl
compound, acid anhydride group-containing (meth)acrylate, hydroxyl
group-containing (meth)acrylate, amido group-containing
(meth)acrylate, amino group-containing (meth)acrylate, epoxy
group-containing (meth)acrylate, N-acryloylmorpholine, and vinyl
ethers may be also used.
[0198] As a ratio of ethylene glycol group-containing
(meth)acrylate contained in an ethylene glycol group-containing
(meth)acrylate polymer, 10 to 70% by weight is preferable. When a
ratio of ethylene glycol group-containing (meth)acrylate is less
than 10% by weight, compatibility with an ionic acid becomes worse,
and sufficient antistatic is not obtained. On the other hand, when
the ratio exceeds 70% by weight, compatibility with an acryl-based
polymer which is a base polymer becomes worse, and sufficient
antistatic is not obtained.
[0199] The aforementioned (meth)acrylate may be used alone, or may
be used by mixing.
[0200] As a molecular weight of the aforementioned ethylene oxide
group-containing polyether-based polymer or ethylene glycol
group-containing (meth)acrylate polymer, a number average molecular
weight of 10000 or less, preferably 200 to 5000 is preferably used.
When a number average molecular weight exceeds 10000, there is a
tendency that stain property onto an adherend is deteriorated. A
number average molecular weight refers to a molecular weight
obtained by measurement by GPC (gel permeation chromatography).
[0201] The aforementioned ethylene oxide group-containing compound
may be used alone, or two or more of them may be used by mixing. An
amount of ethylene oxide group-containing compound to be blended is
0.01 to 10 parts by weight, preferably 0.05 to 5 part by weight
relative to 100 parts by weight of a base polymer. When the amount
is less than 0.01 part by weight, sufficient electrification
property is not obtained and, when the amount exceeds 10 parts by
weight, bleeding onto an adherend is increased, there is a tendency
that an adhesive strength is reduced.
[0202] In addition, in the case where a polymer containing, as a
monomer component, 0.5 to 30% by weight of a nitrogen-containing
monomer and having a glass transition temperature Tg of no higher
than 0.degree. C. is particularly used as the base polymer of a
pressure-sensitive adhesive composition, it is preferable for the
polymer to appropriately contain an alkylene oxide group-containing
compound. When a pressure sensitive adhesive composition contains
the alkylene oxide group-containing compound, in some cases, the
pressure sensitive adhesive composition exhibits better
antistatic.
[0203] An alkylene oxide group-containing compound in the present
invention is not particularly limited, as long as the compound
includes an alkylene oxide group and a surfactant having an
alkylene oxide group, a polyether based polymer that contains an
alkylene oxide group, and an alkylene glycol group-containing a
(meth)acryl-based polymer can be cited as examples. In particular,
the surfactant having an alkylene oxide group which easily provides
a well balanced compatibility between the base polymer and an ionic
liquid is preferably used.
[0204] As the surfactants having an alkylene oxide group, nonionic
surfactants, such as polyoxyalkylene fatty acid esters,
polyoxyalkylene sorbitan fatty acid esters, polyoxyalkylene
sorbitol fatty acid esters, polyoxyalkylene alkyl ethers,
polyoxyalkylene alkyl allyl ethers, polyoxyalkylene alkyl phenyl
ethers, polyoxyalkylene derivatives, polyoxyalkylene alkyl amines,
and polyoxyalkylene alkyl amine fatty acid esters, anionic
surfactants, such as polyoxyalkylene alkyl ether sulfates,
polyoxyalkylene alkyl ether phosphates, and polyoxyalkylene alkyl
phenyl ether phosphates, and cationic surfactants, as well as
cationic and anionic surfactants that include an alkylene oxide
group, for example, can be cited. In addition, these may have a
reactive substituent group, such as a (meth)acryloyl group or an
allyl group.
[0205] It is more preferable to use a surfactant having an ethylene
oxide group in the pressure-sensitive adhesive composition in the
present invention. Previously illustrated surfactants of the
present specification can be cited as specific examples of
surfactants having an ethylene oxide group.
[0206] It is preferable for the number of moles of oxyalkylene
units added of the surfactant having the alkylene oxide group as
described above to be 1 to 50 from the point of view of mutual
interactions with the ionic liquid, and 2 to 40 is more preferable.
In the case where the surfactant does not have an alkylene oxide
group, it is difficult to provide a well balanced compatibility
between an ionic liquid and the base polymer, and this is not
preferable, since bleeding to the adherend tends to increase. On
the other hand, in the case where a surfactant is used of which the
number of moles of the added oxyalkylene units exceeds 50, the
ionic liquid is bound by the alkylene oxide groups, so that the
antistatic tend to be lowered, and this is not preferable.
[0207] The aforementioned surfactants having the alkylene oxide
group may be used alone, or two or more of them may be used by
mixing, and an amount to be blended is preferably 0.01 to 10 parts
by weight, more preferably 0.05 to 5 parts by weight relative to
100 parts by weight of a base polymer. When an amount to be blended
is less than 0.01 part by weight, effect of taking balance between
antistatic and pollution property is hardly obtained and, when the
amount exceeds 10 parts by weight, there is a tendency that stain
onto an adherend is increased by the increas of the bleeding, being
not preferable.
[0208] In the pressure-sensitive adhesive composition of the
present invention, pressure-sensitive adhesive sheets further
excellent in heat resistance are obtained by appropriately
crosslinking a base polymer, in particular, a (meth)acryl-based
polymer. Examples of a specific means for a crosslinking method
include a so-called method of using a crosslinking agent, in which
a compound having a group reactive with a carboxyl group, a
hydroxyl group which is appropriately contained as a crosslinking
basal point in a (meth)acrly-based polymer such as an isocyanate
compound, an epoxy compound, a melanine-based resin and an
aziridine compound is added to react them. Among them, from a
viewpoint mainly of obtaining an appropriate cohesive strength, an
isocyanate compound and an epoxy compound are particularly
preferably used. These compounds may be used alone, or may be used
by mixing two or more kinds of them.
[0209] Among them, examples of the isocyanate compound include
aromatic isocyanate such as tolylene diisocyanate, and xylene
diisocyanate, alicycilc isocyanate such as isophorone diisocyanate
and aliphatic isocyanate such as hexamethylene diisocyanate.
[0210] More specific examples of the isocyanate compound include
lower aliphatic polyisocyanates such as butylene diisocyanate, and
hexamethylene diisocyanate, alicyclic isocyanates such as
cyclopentylene diisocyanate, cyclohexylene diisocyanate, and
isophorone diisocyanate, aromatic diisocyanates such as
2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and
xylene diisocyanate, and isocyanate adducts such as
trimethylolpropane/tolylene diisocyanate trimer adduct (trade name:
Coronate L manufactured by Nippon Polyurethane Industry Co., Ltd.),
trimethylolpropane/hexamethylene diisocyanate trimer adduct (trade
name: Coronate HL manufactured by Nippon Polyurethane Industry Co.,
Ltd.), and isocyanurate of hexamethylene diisocyanate (trade name:
Coronate HX manufactured by Nippon Polyurethane Industry Co.,
Ltd.). These isocyanate compounds may be used alone, or may be used
by mixing two or kinds of them.
[0211] Examples of the epoxy compound include
N,N,N',N'-tetraglycidyl-m-xylenediamine (trade name TETRAD-X
manufactured by Mitsubishi Gas Chemical Company, Inc.) and
1,3-bis(N,N-diglycidylaminomethyl)cyclohexane (trade name TETRAD-C
manufactured by Mitsubishi Gas Chemical Company Inc.). These
compounds may be used alone, or may be used by mixing two or more
kinds.
[0212] Examples of the melamine-based resin include
hexamethylolmelamine.
[0213] Examples of the aziridine derivative include trade name HDU,
trade name TAZM, and trade name TAZO (all manufactured by Sogo
Pharmaceutical Co., Ltd.) as a commercially available product.
These compounds may be used alone, or may be used by mixing two or
more kinds.
[0214] An amount of these crosslinking agents to be used depends on
balance between a (meth)acryl-based polymer to be crosslinked, and
is appropriately selected depending on utility as a
pressure-sensitive adhesive sheet. In order to obtain sufficient
heat resistance due to a cohesive strength of an acryl
pressure-sensitive adhesive, generally, the crosslinking agent is
contained preferably at 0.01 to 15 parts by weight, more preferably
0.5 to 10 parts by weight relative to 100 parts by weight of the
(meth)acryl-based polymer. When a content is less than 0.01 part by
weight, crosslinking formation due to a crosslinking agent becomes
insufficient, a cohesive strength of a pressure-sensitive adhesive
composition becomes small, and sufficient heat resistance is not
obtained in some cases, and there is a tendency that it becomes
cause for an adhesive residue. On the other hand, when a content
exceeds 15 parts by weight, a cohesive strength of a polymer is
great, fluidlity is reduced, and wetting on an adherend becomes
insufficient, and there is a tendency that this becomes cause for
peeling off.
[0215] Alternatively, a polyfunctional monomer containing two or
more radiation-reactive unsaturated bonds as a substantial
crosslinking agent is added, and this may be crosslinked with
radiation.
[0216] As the polyfunctional monomer having two or more
radiation-reactive unsaturated bonds, a polyfunctional monomer
component having two or more of one kind or two or more kinds
radiation-reactive groups which can be crosslinking-treated (cured)
by irradiation of radiation, such as a vinyl group, an acryloyl
group, a methacryloyl group, and a vinylbenzyl group is used.
Generally, a component having 10 or less of radiation-reactive
unsaturated bonds is suitably used. Two or more kinds of the
polyfunctional monomer may be used by mixing.
[0217] Examples of the polyfunctional monomer include ethylene
glycol di(meth)acrylate, diethlene glycol di(meth)acrylate,
tetraethylene glycol di(meth)acrylate, neopentyl glycol
di(meth)acrylate, 1,6-hexanediol di(meth)acrylate,
trimethylolpropane tri(meth)acrylate, pentaerythritol
tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate,
divinylbenzene, and N,N'-methylenebisacrylamide.
[0218] An amount of the polyfunctinoal monomer to be used depends
on balance between a (meth)acryl-based polymer to be crosslinked,
and is appropriately selected depending on utility as a
pressure-sensitive adhesive sheet. In order to obtain sufficient
heat resistance due to a cohesive strength of an acryl
pressure-sensitive adhesive, generally, the monomer is preferably
blended at 0.1 to 30 parts by weight relative to 100 parts by
weight of a (meth)acryl-based polymer. From a viewpoint of
flexibility and tackiness, the monomer is preferably blended at 10
parts by weight or less relative to 100 parts by weight of a
(meth)acryl-based polymer.
[0219] Examples of radiation include ultraviolet ray, laser ray,
.alpha. ray, .beta. ray, .gamma. ray, X-ray, and electron beam.
From a viewpoint of controlling property and better handling
property and a cost, ultraviolet ray is suitably used. More
preferably, ultraviolet ray having a wavelength of 200 to 400 nm is
used. Ultraviolet ray can be irradiated using an appropriate light
source such as a high pressure mercury lamp, a micro-wave
excitation-type lamp, and a chemical lamp. When ultraviolet ray is
used as irradiation, a photopolymerization initiator is added to an
acryl pressure-sensitive adhesive layer.
[0220] The photopolymerization initiator depends on a kind of a
radiation-reactive component, and may be a substance which produces
a radical or a cation by irradiating ultraviolet ray having an
appropriately wavelength which can trigger the polymerization
reaction.
[0221] Example of the photoradical polymerization initiator include
benzoins such as benzoin, benzoin methyl ether, benzoin ethyl
ether, methyl o-benzoylbenzoate-p-benzoin ethyl ether, benzoin
isopropyl ether, and .alpha.-methylbenzoin, acetophenes such as
benzylmethylketal, trichloroacetophenone, 2,2-diethoxyacetophenone,
and 1-hydroxycyclohexyl phenyl ketone, propiophenones such as
2-hydroxy-2-methylpropiophenone, and
2-hydroxy-4'-isopropyl-2-methylpropiophenone, benzophenones such as
benzophenone, methylbenzophenone, p-chlorobenzophenone, and
p-dimethylaminobenzophenone, thioxanthons such as
2-chlorothioxanthon, 2-ethylthioxanthon, and
2-isopropylthioxanthon, acylphosphine oxides such as
bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide,
2,4,6-trimethylbenzoyldiphenylphosphine oxide, and
(2,4,6-trimethylbenzoyl)-(ethoxy)-phenylphosphine oxide, benzil,
dibenzsuberone, and .alpha.-acyloxime ether.
[0222] Examples of a photocation polymerization initiator include
onium salts such as an aromatic diazonium salt, an aromatic
iodonium salt, and an aromatic sulfonium salt, organometallic
complexes such as an ion-allene complex a titanocene complex, and
an aryl silanol-aluminum complex, nitrobenzyl ester, sulfonic acid
derivative, phosphoric acid ester, phenolsulfonic acid ester,
diazonaphthoquinone, and N-hydroxymidosulfonate. Two or more kinds
of the photopolymerization initiators may be used by mixing.
[0223] It is preferably that the photopolymerization initiator is
blended usually in a range of 0.1 to 10 parts by weight, preferably
0.2 to 7 parts by weight relative to 100 parts by weight of a
(meth)acryl-based polymer.
[0224] Further, it is also possible to use a photoinitiation
polymerization assistant such as amines. Examples of the
photoinitiation assistant include 2-dimethylaminoethyl benzoate,
diemethylaminoacetophenone, p-dimethylaminobenzoic acid ethyl
ester, and p-dimethylaminobenzoic acid isoamyl ester. Two or more
kinds of the photopolymerization initiation assistants may be used.
It is preferably that the polymerization initiation assistant is
blended at 0.05 to 10 parts by weight, further 0.1 to 7 parts by
weight relative to 100 parts by weight a (meth)acryl-based
polymer.
[0225] Further, the previously known tackifiers, or the previously
known various additives such as a leveling agent, an antioxidant, a
corrosion preventing agent, a photo stabilizer, an ultraviolet
absorbing agent, a polymerization inhibitor, a silane coupling
agent, and a powder, a particle, and a foil of inorganic or organic
filer, metal powder and pigment may be appropriately added to the
pressure-sensitive adhesive composition used in the
pressure-sensitive adhesive sheet of the present invention
depending on utility.
[0226] Meanwhile, the pressure-sensitive adhesive layer in the
present invention is such that the aforementioned
pressure-sensitive adhesive composition is crosslinked. In
addition, pressure-sensitive adhesive sheets of the present
invention are such that such the pressure-sensitive adhesive layer
is formed on a supporting film. Thereupon, crossslinking of the
pressure-sensitive adhesive composition is generally performed
after coating of the pressure-sensitive adhesive composition, and a
pressure-sensitive adhesive layer composition after crosslinking
may be also transferred onto a supporting film.
[0227] When a photopolymerization initiator as an arbitrary
component is added as described above, a pressure-sensitive
adhesive layer can be obtained by coating the pressure-sensitive
adhesive composition directly on a subject to be protected, or
coating on one side or both sides of a supporting substrate, and
performing light irradiation. Usually, a pressure-sensitive
adhesive layer is used by photopolymerization by irradiating with
ultraviolet ray having an irradiance of 1 to 200 mW/cm.sup.2 at a
wavelength of 300 to 400 nm, at an expose dose of around 200 to
4000 mJ/cm.sup.2.
[0228] A method of forming a pressure-sensitive adhesive layer on a
film is not particularly limited, but for example, a layer is
prepared by coating the aforementioned pressure-sensitive adhesive
composition on a supporting film, and drying this to remove a
polymerization solvent to form a pressure-sensitive adhesive layer
on a supporting film. Thereafter, aging may be performed for the
purpose of adjusting transference of a component of a
pressure-sensitive adhesive layer or adjusting a crosslinking
reaction. Alternatively, when pressure-sensitive adhesive sheets
are prepared by coating a pressure-sensitive adhesive composition
on a supporting film, one or more kinds of solvents other than a
polymerization solvent may be newly added to the composition so
that the composition can be uniformly coated on a supporting
film.
[0229] In addition, as a method of forming the pressure-sensitive
adhesive layer of the present invention, the known method used for
preparing pressure-sensitive adhesive sheets is used. Specifically,
examples include roll coating, gravure coating, reverse coating,
roll brushing, spray coating, and air knife coating methods,
immersing and curtain coating method, and extruding coating method
with a die coater.
[0230] Pressure-sensitive adhesive sheets of the present invention
are such that the aforementioned pressure-sensitive adhesive layer
is coated on one side or both sides of various supports comprising
a plastic film such as a polyester film, or a porous material such
as a paper and a non-woven fabric at a thickness of usually 3 to
100 .mu.m, preferably around 5 to 50 .mu.m, to form an aspect of a
sheet or a tape. In particular, it is preferable to use a plastic
substrate as a support in a case of a surface protecting film.
[0231] The plastic substrate is not particularly limited as far as
it can be formed into a sheet or a film, and examples include a
polyolefin film such as polyethylene, polypropylene, poly-1-butene,
poly-4-methyl-1-pentene, a polybutadiene film, a polymethylpentene
film, an ethylene.propylene copolymer, an ethylene-1-butene
copolymer, an ethylene.vinyl acetate copolymer, an ethylene-ethyl
acrylate copolymer, and an ethylene.vinyl alcohol copolymer, a
polyester film such as polyethylene terephthalate, polyethylene
naphthalate, and polybutylene terephthalate, a polyacrylate film, a
polyurethane film, a polystyrene film, a polyamide film such as
nylon 6, nylon 6,6, and partially aromatic polyamide, a polyvinyl
chloride film, a vinyl chloride copolymer film, a polyvinylidene
chloride film, and a polycarbonate film.
[0232] A thickness of the film is usually 5 to 200 .mu.m,
preferably around 10 to 100 .mu.m.
[0233] The plastic substrate may be subjected to releasing,
anti-staining or acid treatment with silicone, fluorine, long chain
alkyl-based or fatty acid amide-based releasing agent, or a silica
powder, easy adhesion treatment such as alkali treatment, primer
treatment, corona treatment, plasma treatment, and ultraviolet ray
treatment, or coating-type, kneading-type, or deposition-type
antistatic treatment, if necessary.
[0234] In addition, it is more preferably that a plastic substrate
used in the surface protecting film of the present invention is
electrification preventing-treated.
[0235] Antistatic treatment which is performed on a plastic
substrate is not particularly limited, but for example, a method of
providing an electrification preventing layer on at least one side
of a generally used film, or a method of kneading a kneading-type
electrification preventing agent into a plastic film is used.
[0236] Examples of a method of providing an electrification
preventing layer on at least one side of a film include a method of
coating an electrification preventing resin comprising an
electrification preventing agent and a resin component, or an
electrically conductive resin containing an electrically conductive
polymer or an electrically conductive substance, and a method of
depositing or plating an electrically conductive substance.
[0237] Examples of an electrification preventing agent contained in
an electrification preventing resin include a cation-type
electrification preventing agent having a cationic functional group
such as a quaternary ammonium salt, a pyridinium salt, and a
primary, secondary or tertiary amino group, an anion-type
electrification preventing agent having an anionic functional group
such as a sulfonic acid salt, a sulfuric acid ester salt, a
phosphonic acid salt, and a phosphoric ester salt, an
amphoteric-type electrification preventing agent such as
alkylbetain and a derivative thereof, imidazoline and a derivative
thereof, and alanine and a derivative thereof, a nonion-type
electrification preventing agent such as glycerin and a derivative
thereof, and polyethylene glycol and a derivative thereof, and an
ionic electrically conductive polymer obtained by polymerizing or
copolymerizing a monomer having the aforementioned cation-type,
anion-type, or amphoteric-type ionic electrically conductive group.
These compounds may be used alone, or two or more of them may be
used by mixing.
[0238] Specifically, examples of the cation-type electrification
preventing agent include a (meth)acrylate copolymer having a
quaternary ammonium group such as an alkyl trimethylammonium salt,
acyloylamidopropyltrimethtylammonium methosulfate, an
alkylbenzylmethylammonium salt, acyl choline chloride, and
polydimethylaaminoethyl methacrylate, a styrene copolymer having a
quaternary ammonium group such as polyvinylbenzyltrimethylammonium
chloride, and a diallylamine copolymer having a quaternary ammonium
group such as polydiallyldimethylammonium chloride. The compounds
may be used alone, or two or more kinds may be used by mixing.
[0239] Examples of the anion-type electrification preventing agent
include an alkyl sulfonic acid salt, an alkylbenzenesulfonic acid
salt, an alkyl sulfate ester salt, an alkyl ethoxy sulfate ester
salt, an alkyl phosphate ester salt, and a sulfonic acid
group-containing styrene copolymer. These compounds may be used
alone, or two or more kinds may be used by mixing.
[0240] Examples of the amphoteric-type electrification preventing
agent include alkylbetain, alkylimidazoliumbetain, and
carbobetaingrafted copolymer. These compounds may be used alone, or
two or more kinds may be used by mixing.
[0241] Examples of the nonion-type electrification preventing agent
include fatty acid alkylolamide, di(2-hydroxyethyl)alkylamine,
polyoxyethylenealkylamine, fatty acid glycerin ester,
polyoxyethylene glycol fatty acid ester, sorbitan fatty acid ester,
polyoxysorbitan fatty acid ester, polyoxyethylene alkyl phenyl
ether, polyoxyethylene alkyl ether, polyethylene glycol,
polyoxyethylenediamine, a copolymer consisting of polyether,
polyester and polyamide, and methoxypolyethyleneglycol
(meth)acrylate. These compounds may be used alone, or two or more
kinds may be used by mixing.
[0242] Examples of the electrically conductive polymer include
polyaniline, polypyrrole and polythiophene. These electrically
conductive polymers may be used alone, or two or more kinds may be
used by mixing.
[0243] Examples of the electrically conductive substance include
tin oxide, antimony oxide, indium oxide, cadmium oxide, titanium
oxide, zinc oxide, indium, tin, antimony, gold, silver, copper,
aluminum, nickel, chromium, titanium, iron, covert, copper iodide,
and an alloy and a mixture thereof. These electrically conductive
substances may be used alone, or two or more kinds may be used by
mixing.
[0244] As a resin component used in the electrification preventing
resin and the electrically conductive resin, a generally used resin
such as polyester, acryl, polyvinyl, urethane, melanine and epoxy
is used. In the case of a polymer-type electrification preventing
agent, it is not necessary that a resin component is contained. In
addition, the electrification preventing resin component may
contain compounds of a methylolated or alkylolated melanine series,
a urea series, a glyoxal series, and an acrylamide series, an epoxy
compound, or an isocyanate compound as a crosslinking agent.
[0245] An electrification preventing layer is formed, for example,
by diluting the aforementioned electrification preventing resin,
electrically conductive polymer or electrically conductive resin
with a solvent such as an organic solvent and water, and coating
this coating solution on a plastic film, followed by drying.
[0246] Examples of an organic solvent used in formation of the
electrification preventing layer include methyl ethyl ketone,
acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexanone,
n-hexane, toluene, xylene, methanol, ethanol, n-propanol and
isopropanol. These solvents may be used alone, or two or more kinds
may be used by mixing.
[0247] As a coating method in formation of the electrification
preventing layer, the known coating method is appropriately used,
and examples include roll coating, gravure coating, reverse
coating, roll brushing, spray coating, and air knife coating
methods, an immersing and curtain coating method, and an extrusion
coating method with a die coater.
[0248] A thickness of the aforementioned electrification preventing
resin layer, electrically conductive polymer or electrically
conductive resin is usually 0.01 to 5 .mu.m, preferably around 0.03
to 1 .mu.m.
[0249] Examples of a method of depositing or plating an
electrically conductive substance include vacuum deposition,
sputtering, ion plating, chemical deposition, spray pyrolysis,
chemical plating, and electric plating methods.
[0250] A thickness of the electrically conductive substance is
usually 20 to 10000 .ANG., preferably 50 to 5000 .ANG..
[0251] As the kneading-type electrification preventing agent, the
aforementioned electrification preventing agent is appropriately
used.
[0252] An amount of the kneading-type electrification preventing
agent to be blended is 20% by weight or less, preferably in a range
of 0.05 to 10% by weight relative to a total weight of a plastic
film. A kneading method is not particularly limited as far as it is
a method by which the electrification preventing agent can be
uniformly mixed into a resin used in a plastic film, but for
example, a heating roll, a Banbury mixer, a pressure kneader, and a
biaxial kneading machine are used.
[0253] The plastic film may be subjected to releasing,
anti-staining or acid treatment with a silicone-based,
fluorine-based, long chain alkyl-based or fatty acid amide-based
releasing agent, or a silica powder, or easy adhesion treatment
such as alkali treatment, primer treatment, corona treatment,
plasma treatment, and ultraviolet treatment, if necessary.
[0254] If necessary, a separator (or peeling liner, peeling sheet
etc.) can be laminated on a surface of a pressure-sensitive
adhesive for the purpose of protecting a pressure-sensitive
adhesive surface. As a substrate constituting a separator, there
are a paper and a plastic film, and a plastic film is suitably used
from a viewpoint of excellent surface smoothness.
[0255] The film is not particularly limited as far as it is a film
which can protect the pressure-sensitive adhesive layer, and
examples include a polyolefin film such as polyethylene,
polypropylene, poly-1-butene, poly-4-methyl-1-pentene, an
ethylene.propylene copolymer, an ethylene.1-butene copolymer, an
ethylene.vinyl acetate copolymer, an ethylene-ethyl acrylate
copolymer, and an ethylene.vinyl alcohol copolymer, a polyether
film such as polyethylene terephthalate, polyethylene naphthalate,
and polybutylene terephthalate, a polyacrylate film, a polystyrene
film, a polyamide film such as nylon 6, nylon 6,6, and partially
aromatic polyamide, a polyvinyl chloride film, a poly vinylidene
chloride film, and a polycarbonate film.
[0256] A thickness of the film is usually around 5 to 200 .mu.m,
preferably around 10 to 100 .mu.m. A pressure-sensitive adhesive
layer applying surface of the film is appropriately subjected to
treatment with a releasing agent such as a silicone-based,
fluorine-based, long chain alkyl-based, or fatty acid amide-based
releasing agent, or a silica powder.
[0257] The pressure-sensitive adhesive composition, the
pressure-sensitive adhesive layer and the pressure-sensitive
adhesive sheets using the present invention are used, particularly,
in plastic products on which static electricity is easily generated
and, in particular, can be used as a surface protecting film used
for the purpose of protecting an optical member surface such as a
polarizing plate, a wavelength plate, an optical compensating film,
a light diffusion sheet and a reflecting sheet which are used in a
liquid crystal display.
EXAMPLES
[0258] Examples which specifically show a construction and effect
of the present invention will be explained below. Assessment items
in Examples were measured as follows:
<Measurement of Acid Value>
[0259] An acid value was measured using an automatically titrating
apparatus (COM-550 manufactured by HIRANUMA SANGYO Co., Ltd.), and
was obtained by the following equation.
A={(Y-X).times.f.times.5.611}/M
[0260] A; Acid value
[0261] Y; Titration amount of sample solution (ml)
[0262] X; Titration amount of solution of only 50 g of mixed
solvent (ml)
[0263] f; Factor of titration solution
[0264] M; Weight of polymer sample (g)
[0265] Measurement conditions are as follows:
[0266] Sample solution: About 0.5 g of a polymer sample was
dissolved in 50 g of a mixed solvent (toluene/2-propano1/distilled
water=50/49.5/0.5, weight ratio) to obtain a sample solution.
[0267] Titration solution: 0.1N 2-propanolic potassium hydroxide
solution (for petroleum product neutralization value test
manufactured by Wako Pure Chemical Industries, Ltd.)
[0268] Electrode: glass electrode; GE-101, comparative electrode;
RE-201, Measurement mode: petroleum product neutralization value
test 1
<Measurement of Molecular Weight>
[0269] A molecular weight was measured using a GPC apparatus
(HLC-8220GPC manufactured by Tosoh Corporation). Measuring
conditions are as follows.
[0270] Sample concentration: 0.2 wt % (THF solution)
[0271] Sample injection amount: 10 .mu.l
[0272] Eluent: THF
[0273] Flow rate: 0.6 ml/min
[0274] Measuring temperature: 40.degree. C.
[0275] Column:
[0276] Sample column;
[0277] TSKguard column SuperHZ-H(1 column)+TSK gel Super HZM-H(2
columns) Reference column;
[0278] TSK gel SuperH-RC(1 column)
[0279] Detector: Refractive index detector (RI)
[0280] A molecular weight was obtained in terms of polystyrene.
<Analysis of Ionic Liquid Structure>
[0281] Structural analysis of an ionic liquid was performed by NMR
measurement, XRF measurement, and FT-IR measurement.
[NMR Measurement]
[0282] NMR measurement was performed under the following measuring
condition using a nuclear magnetic resonance apparatus (EX-400
manufactured by JEOL. Ltd.).
[0283] Observation frequency: 400 MHz (.sup.1H), 100 MHz
(.sup.13C)
[0284] Measuring solvent: acetone-d.sub.6
[0285] Measuring temperature: 23.degree. C.
[XRF Measurement]
[0286] XRF measurement was performed under the following measuring
condition using a scanning-type fluorescent X-ray analyzing
apparatus (ZSX-100e manufactured by Rigaku Corporation).
[0287] Measuring method: filter paper method
[0288] X-ray source: Rh
[FT-IR Measurement]
[0289] FT-IR measurement was performed under the following
measuring condition using an infrared spectrophotometer (Magna-560
manufactured by Nicolet).
[0290] Measuring method: ATR method
[0291] Detector: DTGS
[0292] Resolution: 4.0 cm.sup.-1
[0293] Accumulation times: 64
[0294] Examples I to III will be explained below.
Example I
<Measurement of Glass Transition Temperature Tg>
[0295] A glass transition temperature Tg(.degree. C.) was obtained
by the following equation using the following reference values as a
glass transition temperature Tg.sub.n(.degree. C.) of a homopolymer
of each monomer.
[0296] Equation: 1/(Tg+273)=.SIGMA.[W.sub.n/(Tg.sub.n+273)]
[0297] [wherein Tg (.degree. C.) represents a glass transition
temperature of a copolymer, W.sub.n (-) represents a weight
fraction of each monomer, Tg, (.degree. C.) represents a glass
transition temperature of a homopolymer of each polymer, and n
represents a kind of each monomer]
[0298] Reference values:
[0299] 2-Ethylhexyl acrylate: -70.degree. C.
[0300] Ethoxy-diethylene glycol acrylate: -70.degree. C.
[0301] 2-Hydroxyethyl acrylate: -15.degree. C.
<Measurement of Glass Transition Temperature Tg of Acryl-Based
Polymer (F) and (G); Measurement of a Dynamic
Viscoelasticity>
[0302] A glass transition temperature Tg(.degree. C.) of
Acryl-based polymer (F) and (G) was obtained by the following
procedures using the measurement of a dynamic visco elasticity.
[0303] Sheets of an acryl-based polymer having a thickness of 25
.mu.m were laminated into a thickness of about 2 mm, this was
punched into .phi.7.9 mm to prepare a cylindrical pellet, and this
was used as a sample for measuring a glass transition temperature
(Tg).
[0304] Using the measuring sample, the measuring sample was fixed
on a jig of a .phi.7.9 mm parallel plate, temperature dependency of
loss elastic modulus G'' was measured with a dynamic
viscoelasticity measuring apparatus (ARES manufactured by
Rheometric Scientific, Inc.), and a temperature at which the
resulting G'' curve became a maximum was adopted as a glass
transition temperature (Tg) (.degree. C.). Measuring conditions are
as follows.
[0305] Measurement: shear mode
[0306] Temperature range: -70.degree. C. to 200.degree. C.
[0307] Temperature raising rate: 5.degree. C./min
[0308] Frequency: 1 Hz
[Preparation of (meth)acryl-Based Polymers]
(Acryl-Based Polymer (A))
[0309] A four-neck flask equipped with a stirring wing, a
thermometer, a nitrogen gas introducing tube, a condenser, and a
dropping funnel was charged with 140 parts by weight of
2-ethylhexyl acrylate, 60 parts by weight of ethoxy-diethylene
glycol acrylate, 8 parts by weight of 2-hydroxyethyl acrylate, 0.4
part by weight of 2,2'-azobisisobutyronitrile as a polymerization
initiator, 218 parts by weight of ethyl acetate, and 94 parts by
weight of toluene, a nitrogen gas was introduced while mildly
stirring, and a polymerization reaction was performed for about 6
hours while maintaining a liquid temperature in a flask at about
65.degree. C., to prepare a solution (40% by weight) of an
acryl-based polymer (A). This acryl-based polymer (A) had
Tg=-68.degree. C., a weight average molecular weight of 500
thousands, and an acid value of 0.0.
(Acryl-Based Polymer (B))
[0310] A four-neck flask equipped with a stirring wing, a
thermometer, a nitrogen gas introducing tube, a condenser, and a
dropping funnel was charged with 200 parts by weight of
ethoxy-diethylene glycol acrylate, 12 parts by weight of
2-hydroxyethyl acrylate, 0.4 part by weight of
2,2'-azobisisobutyronitrile as a polymerization initiator, 197
parts by weight of ethyl acetate, and 197 parts by weight of
toluene, a nitrogen gas was introduced while mildly stirring, and a
polymerization reaction was performed for about 6 hours while
maintaining a liquid temperature in a flask at about 65.degree. C.,
to prepare a solution (35% by weight) of an acryl-based polymer
(B). This acryl-based polymer (B) had Tg=-68.degree. C., a weight
average molecular weight of 430 thousands, and an acid value of
0.0.
(Acryl-Based Polymer (C))
[0311] A four-neck flask equipped with a stirring wing, a
thermometer, a nitrogen gas introducing tube, a condenser, and a
dropping funnel was charged with 200 parts by weight of
2-ethylhexyl acrylate, 8 parts by weight of 2-hydroxyethyl
acrylate, 0.4 part by weight of 2,2'-azobisisobutyronitrile as a
polymerization initiator, and 312 parts by weight of ethyl acetate,
a nitrogen gas was introduced while mildly stirring, and a
polymerization reaction was performed for about 6 hours while
maintaining a liquid temperature in a flask at about 65.degree. C.,
to prepare a solution (40% by weight) of an acryl-based polymer
(C). This acryl-based polymer (C) had Tg=-68.degree. C., a weight
average molecular weight of 500 thousands, and an acid value of
0.0.
(Acryl-Based Polymer (D))
[0312] A four-neck flask equipped with a stirring wing, a
thermometer, a nitrogen gas introducing tube, a condenser, and a
dropping funnel was charged with 190 parts by weight of
2-ethylhexyl acrylate, 10 parts by weight of ethoxy-diethylene
glycol acrylate, 8 parts by weight of 2-hydroxyethyl acrylate, 0.4
part by weight of 2,2'-azobisisobutyronitrile as a polymerization
initiator, and 312 parts by weight of ethyl acetate, a nitrogen gas
was introduced while mildly stirring, and a polymerization reaction
was performed for about 6 hours while maintaining a liquid
temperature in a flask at about 65.degree. C., to prepare a
solution (40% by weight) of an acryl-based polymer (D). This
acryl-based polymer (D) had Tg=-68.degree. C., a weight average
molecular weight of 680 thousands, and an acid value of 0.0.
(Acryl-Based Polymer (E))
[0313] A four-neck flask equipped with a stirring wing, a
thermometer, a nitrogen gas introducing tube, a condenser, and a
dropping funnel was charged with 180 parts by weight of
2-ethylhexyl acrylate, 20 parts by weight of ethoxy-diethylene
glycol acrylate, 8 parts by weight of 2-hydroxyethyl acrylate, 0.4
part by weight of 2,2'-azobisisobutyronitrile as a polymerization
initiator, 265 parts by weight of ethyl acetate, and 47 parts by
weight of toluene, a nitrogen gas was introduced while mildly
stirring, and a polymerization reaction was performed for about 6
hours while maintaining a liquid temperature in a flask at about
65.degree. C., to prepare a solution (40% by weight) of an
acryl-based polymer (E). This acryl-based polymer (E) had
Tg=-68.degree. C., a weight average molecular weight of 510
thousands, and an acid value of 0.0.
(Acryl-Based Polymer (F))
[0314] A four-neck flask equipped with a stirring wing, a
thermometer, a nitrogen gas introducing tube, a condenser, and a
dropping funnel was charged with 199 parts by weight of
2-ethylhexyl acrylate, 1 part by weight of methoxy polyethylene
glycol monoacrylate (manufactured by NOF Corporation, Blemmer
PME-1000, number of EO moles added to: approximately 23), 8 parts
by weight of 2-hydroxyethyl acrylate, 0.4 part by weight of
2,2'-azobisisobutyronitrile as a polymerization initiator, and 387
parts by weight of ethyl acetate, a nitrogen gas was introduced
while mildly stirring, and a polymerization reaction was performed
for about 6 hours while maintaining a liquid temperature in a flask
at about 65.degree. C., to prepare a solution (35% by weight) of an
acryl-based polymer (F). This acryl-based polymer (F) had a Tg of
no higher than 0.degree. C., a weight average molecular weight of
490 thousands, and an acid value of 0.0.
(Acryl-Based Polymer (G))
[0315] A four-neck flask equipped with a stirring wing, a
thermometer, a nitrogen gas introducing tube, a condenser, and a
dropping funnel was charged with 199.4 parts by weight of
2-ethylhexyl acrylate, 0.6 part by weight of methoxy polyethylene
glycol monoacrylate (manufactured by NOF Corporation, Blemmer
PME-1000, number of EO moles added to: approximately 23), 8 parts
by weight of 2-hydroxyethyl acrylate, 0.4 part by weight of
2,2'-azobisisobutyronitrile as a polymerization initiator, and 387
parts by weight of ethyl acetate, a nitrogen gas was introduced
while mildly stirring, and a polymerization reaction was performed
for about 6 hours while maintaining a liquid temperature in a flask
at about 65.degree. C., to prepare a solution (35% by weight) of an
acryl-based polymer (G). This acryl-based polymer (G) had a Tg of
no higher than 0.degree. C., a weight average molecular weight of
490 thousands, and an acid value of 0.0.
[Preparation of Ionic Liquids]
(Ionic Liquid (a))
[0316] A 20% by weight aqueous solution of 10 parts by weight of
1-butyl-3-methylimidazolium bromide (manufactured by Tokyo Kasei
Kogyo Co., Ltd.) was added to four-neck flask equipped with a
stirring wing, a thermometer, and a condenser, and a 20% by weight
aqueous solution of 19 parts by weight of lithium
bis(trifluoromethanesulfonyl)imide (manufactured by Kishida
Chemical Co., Ltd.) was gradually added while rotating a stirring
wing. After addition, stirring was continued at 25.degree. C. for 2
hours, and this was allowed to stand for 12 hours. Then, the
supernatant was removed to obtain a liquid product.
[0317] The resulting liquid product was washed with 200 parts by
weight of distilled water three times, and dried for 2 hours under
the environment of 110.degree. C. to obtain 20 parts by weight of
an ionic liquid (a) which is liquid at 25.degree. C. NMR (.sup.1H,
.sup.13C) measurement, FT-IR measurement, and XRF measurement of
the resulting ionic liquid (a) were performed, and
1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide was
identified and confirmed.
(Ionic Liquid (b))
[0318] A 20% by weight aqueous solution of 10 parts by weight of
1-butyl-3-methylpyridinium chloride (manufactured by Wako Pure
Chemical Industries, Ltd.) was added to four-neck flask equipped
with a stirring wing, a thermometer, and a condenser, and a 20% by
weight aqueous solution of 19 parts by weight of lithium
bis(trifluoromethanesulfonyl)imide (manufactured by Kishida
Chemical Co., Ltd.) was gradually added while rotating a stirring
wing. After addition, stirring was continued at 25.degree. C. for 2
hours, and this was allowed to stand for 12 hours. Then, the
supernatant was removed to obtain a liquid product.
[0319] The resulting liquid product was washed with 200 parts by
weight of distilled water three times, and dried for 2 hours under
the environment of 110.degree. C. to obtain 20 parts by weight of
an ionic liquid (b) which is liquid at 25.degree. C. NMR (.sup.1H,
.sup.13C) measurement, FT-IR measurement, and XRF measurement of
the resulting ionic liquid (b) were performed, and
1-butyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imide was
identified and confirmed.
[Preparation of Antistatic Agent Solutions]
(Antistatic Agent Solution (a))
[0320] A four-neck flask equipped with a stirring wing, a
thermometer, and a condenser was charged with 5 parts by weight of
N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium
bis(trifluoromethanesulfonyl)imide (manufactured by Kanto Chemical
Co., Inc, liquid at 25.degree. C.), 5 parts by weight of a nonionic
reactive surfactant (manufactured by Asahi Denka Co,. Ltd., ADEKA
REASOAP NE-10), and 90 parts by weight of ethyl acetate, and mixing
and stirring were performed for 30 minutes while maintaining a
liquid temperature in a flask at around normal temperature
(25.degree. C.) to prepare a solution (10% by weight) of an
antistatic agent solution (a).
(Antistatic Agent Solution (b))
[0321] A four-neck flask equipped with a stirring wing, a
thermometer, and a condenser was charged with 5 parts by weight of
N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium
bis(trifluoromethanesulfonyl)imide (manufactured by KANTO Chemical
Co., Inc, liquid at 25.degree. C.), 5 parts by weight of a nonionic
reactive surfactant (manufactured by Asahi Denka Co,. Ltd., ADEKA
REASOAP ER-10), and 90 parts by weight of ethyl acetate, and mixing
and stirring were performed for 30 minutes while maintaining a
liquid temperature in a flask at around normal temperature
(25.degree. C.) to prepare a solution (10% by weight) of an
antistatic agent solution (b).
(Antistatic Agent Solution (c))
[0322] A four-neck flask equipped with a stirring wing, a
thermometer, and a condenser was charged with 10 parts by weight of
lauryl trimethyl ammonium chloride (manufactured by Tokyo Kasei
Kogyo Co., Ltd., solid at 25.degree. C.), and 90 parts by weight of
isopropyl alcohol, and mixing and stirring were performed for 30
minutes while maintaining a liquid temperature in a flask at around
normal temperature (25.degree. C.) to prepare a solution (10% by
weight) of an antistatic agent solution (c).
(Antistatic Agent Solution (d))
[0323] Ten parts by weight of lauryl trimethyl ammonium chloride
(manufactured by Tokyo Kasei Kogyo Co., Ltd., solid at 25.degree.
C.) which is a cationic surfactant was distilled with 20 parts by
weight of ethyl acetate and 20 parts by weight of isopropyl
alcohol, and whereby, an antistatic agent solution (d) (20% by
weight) was prepared.
(Antistatic Agent Solution (e))
[0324] A four-neck flask equipped with a stirring wing, a
thermometer, and a condenser was charged with 0.2 part by weight of
lithium perchlorate, 9.8 parts by weight of polypropylene glycol
(diol type, number average molecular weight: 2000), and 10 parts by
weight of ethyl acetate, and mixing and stirring were performed for
2 hours while maintaining a temperature of a liquid in a flask at
around 80.degree. C., to prepare an antistatic agent solution (e)
(50% by weight).
[Preparation of Antistatic-Treated Film]
(Antistatic-Treated Film)
[0325] 1 Parts by weight of an antistatic agent (Microsolver
RMd-142 manufactured by Solvex Co., Ltd.; a main component is tin
oxide and polyester resin) was diluted with a mixed solvent
containing 30 parts by weight of water and 70 parts by weight of
methanol to prepare an antistatic agent solution.
[0326] The resulting antistatic agent solution was coated on a
polyethylene terephthalate (PET) film (thickness 38 .mu.m) using a
Meyer bar, and this was dried at 130.degree. C. for 1 minute to
remove a solvent, to form an antistatic layer (thickness 0.2
.mu.m), whereby, an antistatic-treated film was prepared.
Example I-1
(Preparation of Pressure-Sensitive Adhesive Composition)
[0327] A solution (40% by weight) of the aforementioned acryl based
polymer (A) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 0.2 part by
weight of 1-hexyl-3-methyl imidazolium trifluoromethane sulfonate
(manufactured by ACROS Organics Corporation, liquid at 25.degree.
C.), 0.6 part by weight of an isocyanurate of hexamethylene
diisocyanate (manufactured by Nippon Polyurethane Industry Co.,
Ltd, Coronate HX), and 0.4 part by weight of tin dibutyl dilaurate
(1% by weight of ethyl acetate solution), which is a crosslinking
catalyst, which was mixed and stirred for approximately 1 minute at
room temperature (25.degree. C.), and whereby, an acryl
pressure-sensitive adhesive solution (1) was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0328] The aforementioned acryl pressure-sensitive adhesive
solution (1) was coated on a side opposite to an antistatic-treated
side of the antistatic-treated film obtained in Preparation
described above, and this was heated at 110.degree. C. for 3
minutes to form a pressure-sensitive adhesive layer having a
thickness of 20 cm. Then, a silicone-treated side of a polyethylene
terephthalate film having a thickness of 25 .mu.m which had been
subjected to silicone-treated was laminated on one side of a
surface of the aforementioned pressure sensitive adhesive layer to
prepare a pressure-sensitive adhesive sheet.
Example I-2
(Preparation of Pressure-Sensitive Adhesive Composition)
[0329] A solution (40% by weight) of the aforementioned acryl based
polymer (A) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 0.3 part by
weight of aforementioned ionic liquid (a) (liquid at 25.degree.
C.), 0.4 part by weight of an isocyanurate of hexamethylene
diisocyanate (manufactured by Nippon Polyurethane Industry Co.,
Ltd, Coronate HX), and 0.4 part by weight of tin dibutyl dilaurate
(1% by weight of ethyl acetate solution), which is a crosslinking
catalyst, which was mixed and stirred for approximately 1 minute at
room temperature (25.degree. C.), and whereby, an acryl
pressure-sensitive adhesive solution (2) was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0330] According to the same manner as that of Example I-1 except
that the acryl pressure-sensitive adhesive solution (2) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Example I-3
(Preparation of Pressure-Sensitive Adhesive Composition)
[0331] An acryl pressure-sensitive adhesive solution (3) was
prepared in the same manner as in Example I-2, except that 0.3 part
by weight of N,N-diethyl -N-methyl-N-(2-methoxy ethyl) ammonium
bis(trifluoromethanesulfonyl) imide (manufactured by Kanto Chemical
Co., Inc, liquid at 25.degree. C.) was used in place of 0.3 part by
weight of the aforementioned ionic liquid (a).
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0332] According to the same manner as that of Example I-1 except
that the acryl pressure-sensitive adhesive solution (3) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Example I-4
(Preparation of Pressure-Sensitive Adhesive Composition)
[0333] The aforementioned solution (35% by weight) of acryl based
polymer (B) was diluted to 20% by weight with ethyl acetate, and to
100 parts by weight of this solution were added 1.2 parts by weight
of 1-hexyl-3-methyl imidazolium trifluoromethane sulfonate
(manufactured by ACROS Organics Corporation, liquid at 25.degree.
C.), 0.4 part by weight of an isocyanurate of hexamethylene
diisocyanate (manufactured by Nippon Polyurethane Industry Co.,
Ltd, Coronate HX), and 0.4 part by weight of tin dibutyl dilaurate
(1% by weight of ethyl acetate solution), which is a crosslinking
catalyst, which was mixed and stirred for approximately 1 minute at
room temperature (25.degree. C.), and whereby, an acryl
pressure-sensitive adhesive solution (4) was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0334] According to the same manner as that of Example I-1 except
that the acryl pressure-sensitive adhesive solution (4) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Example I-5
(Preparation of Pressure-Sensitive Adhesive Composition)
[0335] A solution (40% by weight) of the aforementioned acryl based
polymer (A) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 6.0 parts by
weight of the aforementioned antistatic agent solution (a) (10% by
weight), 0.5 part by weight of an isocyanurate of hexamethylene
diisocyanate (manufactured by Nippon Polyurethane Industry Co.,
Ltd, Coronate HX), and 0.4 part by weight of tin dibutyl dilaurate
(1% by weight of ethyl acetate solution), which is a crosslinking
catalyst, which was mixed and stirred for approximately 1 minute at
room temperature (25.degree. C.), and whereby, an acryl
pressure-sensitive adhesive solution (5) was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0336] According to the same manner as that of Example I-1 except
that the acryl pressure-sensitive adhesive solution (5) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Example I-6
(Preparation of Pressure-Sensitive Adhesive Composition)
[0337] According to the same manner as that of Example I-5 except
that 6.0 parts by weight of the aforementioned antistatic agent
solution (b) (10% by weight) was used in place of 6.0 parts by
weight of the aforementioned antistatic agent solution (a) (10% by
weight), an acryl pressure-sensitive adhesive solution (6) was
prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0338] According to the same manner as that of Example I-1 except
that the acryl pressure-sensitive adhesive solution (6) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Comparative Example I-1
(Preparation of Pressure-Sensitive Adhesive Composition)
[0339] The aforementioned solution (40% by weight) of acryl based
polymer (C) was diluted to 20% by weight with ethyl acetate, and to
100 parts by weight of this solution were added 0.1 part by weight
of 1-hexyl-3-methyl imidazolium trifluoromethane sulfonate
(manufactured by ACROS Organics Corporation, liquid at 25.degree.
C.), 0.8 part by weight of an isocyanurate of hexamethylene
diisocyanate (manufactured by Nippon Polyurethane Industry Co.,
Ltd, Coronate HX), and 0.4 part by weight of tin dibutyl dilaurate
(1% by weight of ethyl acetate solution), which is a crosslinking
catalyst, which was mixed and stirred for approximately 1 minute at
room temperature (25.degree. C.), and whereby, an acryl
pressure-sensitive adhesive solution (7) was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0340] According to the same manner as that of Example I-1 except
that the acryl pressure-sensitive adhesive solution (7) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Comparative Example I-2
(Preparation of Pressure-Sensitive Adhesive Composition)
[0341] A solution (40% by weight) of the aforementioned acryl based
polymer (C) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 0.2 part by
weight of aforementioned ionic liquid (a) (liquid at 25.degree.
C.), 0.4 part by weight of an isocyanurate of hexamethylene
diisocyanate (manufactured by Nippon Polyurethane Industry Co.,
Ltd, Coronate HX), and 0.4 part by weight of tin dibutyl dilaurate
(1% by weight of ethyl acetate solution), which is a crosslinking
catalyst, which was mixed and stirred for approximately 1 minute at
room temperature (25.degree. C.), and whereby, an acryl
pressure-sensitive adhesive solution (8) was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0342] According to the same manner as that of Example I-1 except
that the acryl pressure-sensitive adhesive solution (8) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Comparative Example I-3
(Preparation of Pressure-Sensitive Adhesive Composition)
[0343] An acryl pressure-sensitive adhesive solution (9) was
prepared in the same manner as in Comparative Example I-2, except
that 0.2 part by weight of N,N-diethyl-N-methyl-N-(2-methoxy
ethyl)ammonium bis(trifluoromethanesulfonyl) imide (manufactured by
Kanto Chemical Co., Inc, liquid at 25.degree. C.) was used in place
of 0.2 part by weight of the aforementioned ionic liquid (a).
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0344] According to the same manner as that of Example I-1 except
that the acryl pressure-sensitive adhesive solution (9) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Comparative Example I-4
(Preparation of Pressure-Sensitive Adhesive Composition)
[0345] An acryl pressure sensitive adhesive solution (10) was
prepared in the same manner as in Comparative Example I-3, except
that 0.02 part by weight of N,N-diethyl-N-methyl-N-(2-metoxyethyl)
ammonium bis(trifluoromethanesulfonyl) imide (manufactured by Kanto
Chemical Co., Inc, liquid at 25.degree. C.) was used in place of
0.2 part by weight of the aforementioned
N,N-diethyl-N-methyl-N-(2-metoxyethyl) ammonium
bis(trifluoromethanesulfonyl) imide (manufactured by Kanto Chemical
Co., Inc, liquid at 25.degree. C.).
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0346] According to the same manner as that of Example I-1 except
that the acryl pressure-sensitive adhesive solution (10) was used
in place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Comparative Example I-5
(Preparation of Pressure-Sensitive Adhesive Composition)
[0347] According to the same manner as that of Example I-2 except
that 10.0 parts by weight of the aforementioned antistatic agent
solution (c) (10% by weight) was used in place of 0.3 part by
weight of the aforementioned aionic liquid (a), an acryl
pressure-sensitive adhesive solution (11) was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0348] According to the same manner as that of Example I-1 except
that the acryl pressure-sensitive adhesive solution (11) was used
in place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Example I-7
(Preparation of Pressure-Sensitive Adhesive Composition)
[0349] A solution (40% by weight) of the aforementioned acryl based
polymer (A) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 0.3 part by
weight of aforementioned ionic liquid (b) (liquid at 25.degree.
C.), 0.4 part by weight of an isocyanurate of hexamethylene
diisocyanate (manufactured by Nippon Polyurethane Industry Co.,
Ltd, Coronate HX), and 0.4 part by weight of tin dibutyl dilaurate
(1% by weight of ethyl acetate solution), which is a crosslinking
catalyst, which was mixed and stirred for approximately 1 minute at
room temperature (25.degree. C.), and whereby, an acryl
pressure-sensitive adhesive solution (12) was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0350] According to the same manner as that of Example I-1 except
that the acryl pressure-sensitive adhesive solution (12) was used
in place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Example I-8
(Preparation of Pressure-Sensitive Adhesive Composition)
[0351] A solution (40% by weight) of the aforementioned acryl based
polymer (D) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 0.2 part by
weight of aforementioned ionic liquid (b) (liquid at 25.degree.
C.), 0.4 part by weight of an isocyanurate of hexamethylene
diisocyanate (manufactured by Nippon Polyurethane Industry Co.,
Ltd, Coronate HX), and 0.4 part by weight of tin dibutyl dilaurate
(1% by weight of ethyl acetate solution), which is a crosslinking
catalyst, which was mixed and stirred for approximately 1 minute at
room temperature (25.degree. C.), and whereby, an acryl
pressure-sensitive adhesive solution (13) was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0352] According to the same manner as that of Example I-1 except
that the acryl pressure-sensitive adhesive solution (13) was used
in place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Example I-9
[0353] An acryl pressure-sensitive adhesive solution was prepared
in accordance with the same method as that in Example I-8, except
that a solution (40% by weight) of the aforementioned acryl based
polymer (E) was used instead of the solution (40% by weight) of the
aforementioned acryl based polymer (D), and a pressure-sensitive
adhesive sheet was prepared in the same method as in Example I-8
using this.
Example I-10
[0354] An acryl pressure-sensitive adhesive solution was prepared
in accordance with the same method as that in Example I-8, except
that a solution (35% by weight) of the aforementioned acryl based
polymer (F) was used instead of the solution (40% by weight) of the
aforementioned acryl based polymer (D), and a pressure-sensitive
adhesive sheet was prepared in the same method as in Example I-8
using this.
Example I-11
[0355] An acryl pressure-sensitive adhesive solution was prepared
in accordance with the same method as that in Example I-8, except
that a solution (35% by weight) of the aforementioned acryl based
polymer (G) was used instead of the solution (40% by weight) of the
aforementioned acryl based polymer (D), and a pressure-sensitive
adhesive sheet was prepared in the same method as in Example I-8
using this.
Comparative Example I-6
(Preparation of Pressure-Sensitive Adhesive Composition)
[0356] A solution (40% by weight) of the aforementioned acryl based
polymer (C) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 0.2 part by
weight of aforementioned ionic liquid (b) (liquid at 25.degree.
C.), 0.4 part by weight of an isocyanurate of hexamethylene
diisocyanate (manufactured by Nippon Polyurethane Industry Co.,
Ltd, Coronate HX), and 0.4 part by weight of tin dibutyl dilaurate
(1% by weight of ethyl acetate solution), which is a crosslinking
catalyst, which was mixed and stirred for approximately 1 minute at
room temperature (25.degree. C.), and whereby, an acryl
pressure-sensitive adhesive solution (14) was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0357] According to the same manner as that of Example I-1 except
that the acryl pressure-sensitive adhesive solution (14) was used
in place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Comparative Example I-7
[0358] An acryl pressure-sensitive adhesive solution was prepared
in the same manner as in Example I-8, except that 0.2 part by
weight of the aforementioned ionic liquid (b) was not used, and a
pressure-sensitive adhesive sheet was fabricated in the same method
as in Example I-8 using this.
Comparative Example I-8
[0359] An acryl pressure-sensitive adhesive solution was prepared
in the same manner as in Example I-9, except that 0.2 part by
weight of the aforementioned ionic liquid (b) was not used, and a
pressure-sensitive adhesive sheet was fabricated in the same method
as in Example I-8 using this.
Comparative Example I-9
[0360] An acryl pressure-sensitive adhesive solution was prepared
in the same manner as in Comparative Example I-6, except that 1.0
parts by weight of the aforementioned antistatic agent solution (d)
(20% by weight) was used in place of 0.2 part by weight of the
aforementioned ionic liquid (b), and a pressure-sensitive adhesive
sheet was fabricated in the same method as in Comparative Example
I-6 using this.
Comparative Example I-10
(Preparation of Pressure-Sensitive Adhesive Composition)
[0361] A solution (40% by weight) of the aforementioned acryl based
polymer (C) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 4 parts by
weight of aforementioned antistatic agent solution (e) (50% by
weight), 0.53 part by weight of a trimethylolpropane/tolylene
diisocyanate trimer adduct (manufactured by Nippon Polyurethane
Industry Co., Ltd, Coronate L), and 0.4 part by weight of tin
dibutyl dilaurate (1% by weight of ethyl acetate solution), which
is a crosslinking catalyst, which was mixed and stirred for
approximately 1 minute at room temperature (25.degree. C.), and
whereby, an acryl pressure-sensitive adhesive solution (15) was
prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0362] According to the same manner as that of Example I-1 except
that the acryl pressure-sensitive adhesive solution (15) was used
in place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
[0363] Regarding the pressure-sensitive adhesive sheets obtained in
the aforementioned Examples and Comparative Examples, a peeling
electrification voltage, staining property, and an adhesive
strength were assessed under the following conditions.
<Measurement of Peeling Electrification Voltage>
[0364] A pressure-sensitive adhesive sheet was cut into a size of a
width of 70 mm and a length of 130 mm, a separator was peeled, and
this was adhered to a surface of a polarizing plate (SEG1425EWVGS2B
manufactured by Nitto Denko Corporation, width: 70 mm, length: 100
mm) laminated to an acryl plate (Acrylite manufactured by
Mitsubishi Rayon Co., Ltd, thickness: 1 mm, width: 70 mm, length:
100 mm) from which electricity had been removed in advance, with a
hand roller, so that one end was protruded by 30 mm.
[0365] After allowed to stand for one day under the environment of
23.degree. C..times.50% RH, and a sample was set at a prescribed
position as shown in FIG. 1. One end protruding by 30 mm was fixed
on an automatic winding machine, and a sample was peeled at a
peeling angle of 150.degree. and a peeling rate of 10 m/min. A
voltage at a polarizing plate surface generated thereupon was
measured with an electrostatic voltmeter (KSD-0103 manufactured by
Kasuga Denka, INC.) fixed at a prescribed position. Measurement was
performed under the environment of 23.degree. C..times.50% RH.
<Assessment of Staining Property>
[0366] A pressure-sensitive adhesive sheet was cut into a size of a
width of 30 mm and a length of 80 mm, a separator was peeled, and
this was adhered on a surface of a polarizing plate
(SEG1425EWVAGS2B manufactured by Nitto Denko Corporation, width: 70
mm, length: 100 mm), with a hand roller, to prepare an assessment
sample.
[0367] The aformentioned assessment sample was allowed to stand for
24 hours under the environment 50.degree. C..times.92% RH and,
thereafter, the pressure-sensitive adhesive sheet was peeled from
an adherend with a hand, and staining state of an adherend surface
thereupon was observed with naked eyes. Assessment criteria are as
follows:
[0368] Case of observation of no staining: .smallcircle.
[0369] Case of observation of staining: x
<Measurement of Adhesive Strength>
[0370] A triacetylcellulose film (FujiTAC manufactured by Fuji
Photo Film Co., Ltd., thickness: 90 .mu.m) was cut into size of a
width of 70 mm and a length of 100 mm, this was immersed in an
aqueous sodium hydroxide solution (10% by weight) at 60.degree. C.
for 1 minute, and washed with distilled water to prepare an
adherend.
[0371] The adherend was allowed to stand for 24 hours under the
environment of 23.degree. C..times.50%RH, and a pressure-sensitive
adhesive sheet which had been cut into a size of a width of 25 mm
and a length of 100 mm was laminated on the adherend at a pressure
of 0.25 MPa to prepare an assessment sample.
[0372] After allowing to stand for 30 minutes under the environment
of 23.degree. C..times.50% RH after the lamination, an adhesive
strength when peeled with a universal tensile testing machine at a
peeling rate of 10 m/min and a peeling angle of 180.degree. was
measured. Measurement was performed under the environment of
23.degree. C..times.50% RH.
[0373] The results of the above are shown in Table 1.
TABLE-US-00001 TABLE 1 peeling staining adhesive electrification
property strength voltage [kV] [-] [N/25 mm] Example I-1 0.0
.smallcircle. 0.4 Example I-2 -0.3 .smallcircle. 0.9 Example I-3
0.0 .smallcircle. 0.9 Example I-4 -0.4 .smallcircle. 0.6 Example
I-5 0.0 .smallcircle. 0.6 Example I-6 0.0 .smallcircle. 0.5 Example
I-7 -0.3 .smallcircle. 0.9 Example I-8 0.0 .smallcircle. 1.2
Example I-9 0.0 .smallcircle. 1.3 Example I-10 0.0 .smallcircle.
0.9 Example I-11 0.0 .smallcircle. 1.0 Comparative 0.0 x 0.4
Example I-1 Comparative 0.0 x 0.8 Example I-2 Comparative -0.3 x
0.8 Example I-3 Comparative -0.9 .smallcircle. 0.9 Example I-4
Comparative 0.0 x 0.5 Example I-5 Comparative 0.0 x 1.6 Example I-6
Comparative -1.2 .smallcircle. 1.4 Example I-7 Comparative -1.0
.smallcircle. 1.4 Example I-8 Comparative 0.0 x 0.3 Example I-9
Comparative 0.0 x 0.5 Example I-10
[0374] As can be seen from the results shown in the aforementioned
Table 1, in the case where the pressure-sensitive adhesive
composition manufactured in the present invention was used
(Examples I-1 to I-11), it is clear that the peeling
electrification voltage of a polarizing plate was suppressed, and
staining on a polarizing plate did not occur in any of the
Examples.
[0375] In contrast to this, in the case where a pressure-sensitive
adhesive composition where the (meth)acryl-based polymer did not
contain a (meth)acrylic acid alkylene oxide as monomer units is
used (Comparative Examples I-1 to I-3 and I-6), and in Comparative
Examples I-5 to I-9, where a cation type surfactant was used as an
antistatic agent, the results showed that the occurrence of
staining was recognized, although the peeling electrification
voltage was suppressed. In addition, in Comparative Example I-4,
where the amount of antistatic agent was reduced in the
pressure-sensitive adhesive composition where the (meth)acryl
polymer did not contain (meth)acrylic acid alkylene oxide as
monomer units, the results showed that although the occurrence of
staining was not recognized, the peeling electrification voltage
had become high. Furthermore, in Comparative Examples I-7 and I-8,
where no ionic liquid was utilized, the results showed that the
peeling electrification voltage had become high. Furthermore, in
Comparative Example I-10, where an antistatic agent containing the
polyether polyol and the alkali metal salt was used, staining
occurred due to bleeding. Accordingly, in any of Comparative
Examples, the results showed that restriction of the peeling
electrification voltage of the polarizing plate which is an
adherend, and prevention of staining could not both be
achieved.
Example II
<Measurement of Glass Transition Temperature Tg>
[0376] The glass transition temperature Tg (.degree. C.) of the
polymer was found with the following equation using the following
reference values as a glass transition temperature
Tg.sub.n(.degree. C.) of a homopolymer of each monomer. Here, no
reference value was found for N-cyclohexyl maleimide, and the glass
transition temperature thereof was determined using a Measurement
of a dynamic viscoelasticity.
[0377] Equation: 1/(Tg+273)=.SIGMA.[W.sub.n/(Tg.sub.n+273)]
[0378] [wherein Tg (.degree. C.) represents a glass transition
temperature of a copolymer, W.sub.n (-) represents a weight
fraction of each monomer, Tg.sub.n (.degree. C.) represents a glass
transition temperature of a homopolymer of each polymer, and n
represents a kind of each monomer]
[0379] Reference values:
[0380] 2-Ethyl hexyl acrylate: -70.degree. C.
[0381] 2-Hydroxy ethyl acrylate: -15.degree. C.
[0382] N,N-Diethyl acryl amide: 81.degree. C.
[0383] Diacetone acryl amide: 77.degree. C.
[0384] Acryloyl morpholine: 145.degree. C.
<Measurement of a Dynamic Viscoelasticity>
[0385] The glass transition temperature (Tg) (.degree. C.) of a
polymer that contains N-cyclohexyl maleimide was determined based
on the measurement of a dynamic viscoelasticity that is described
in Example I.
[Preparation of (meth)acryl-Based Polymers]
(Acryl-Based Polymer (A))
[0386] A four-neck flask equipped with a stirring wing, a
thermometer, a nitrogen gas introducing tube, a condenser, and a
dropping funnel was charged with 190 parts by weight of
2-ethylhexyl acrylate, 10 parts by weight of N,N-diethyl acryl
amide, 8 parts by weight of 2-hydroxyethyl acrylate, 0.4 part by
weight of 2,2'-azobisisobutyronitrile as a polymerization
initiator, and 312 parts by weight of ethyl acetate, a nitrogen gas
was introduced while mildly stirring, and a polymerization reaction
was performed for about 5 hours while maintaining a liquid
temperature in a flask at about 60.degree. C., to prepare a
solution (40% by weight) of an acryl-based polymer (A). This
acryl-based polymer (A) had Tg=-64.degree. C., a weight average
molecular weight of 620 thousands, and an acid value of 0.0.
(Acryl-Based Polymer (B))
[0387] A four-neck flask equipped with a stirring wing, a
thermometer, a nitrogen gas introducing tube, a condenser, and a
dropping funnel was charged with 190 parts by weight of
2-ethylhexyl acrylate, 10 parts by weight of diacetone acryl amide,
8 parts by weight of 2-hydroxyethyl acrylate, 0.4 part by weight of
2,2'-azobisisobutyronitrile as a polymerization initiator, and 312
parts by weight of ethyl acetate, a nitrogen gas was introduced
while mildly stirring, and a polymerization reaction was performed
for about 5 hours while maintaining a liquid temperature in a flask
at about 60.degree. C., to prepare a solution (40% by weight) of an
acryl-based polymer (B). This acryl-based polymer (B) had
Tg=-64.degree. C., a weight average molecular weight of 730
thousands, and an acid value of 0.0.
(Acryl-Based Polymer (C))
[0388] A four-neck flask equipped with a stirring wing, a
thermometer, a nitrogen gas introducing tube, a condenser, and a
dropping funnel was charged with 190 parts by weight of
2-ethylhexyl acrylate, 10 parts by weight of acryloyl morpholine, 8
parts by weight of 2-hydroxyethyl acrylate, 0.4 part by weight of
2,2'-azobisisobutyronitrile as a polymerization initiator, and 312
parts by weight of ethyl acetate, a nitrogen gas was introduced
while mildly stirring, and a polymerization reaction was performed
for about 5 hours while maintaining a liquid temperature in a flask
at about 60.degree. C., to prepare a solution (40% by weight) of an
acryl-based polymer (C). This acryl-based polymer (C) had
Tg=-63.degree. C., a weight average molecular weight of 730
thousands, and an acid value of 0.0.
(Acryl-Based Polymer (D))
[0389] A four-neck flask equipped with a stirring wing, a
thermometer, a nitrogen gas introducing tube, a condenser, and a
dropping funnel was charged with 190 parts by weight of
2-ethylhexyl acrylate, 10 parts by weight of N-cyclohexyl
maleimide, 8 parts by weight of 2-hydroxyethyl acrylate, 0.4 part
by weight of 2,2'-azobisisobutyronitrile as a polymerization
initiator, and 312 parts by weight of ethyl acetate, a nitrogen gas
was introduced while mildly stirring, and a polymerization reaction
was performed for about 5 hours while maintaining a liquid
temperature in a flask at about 60.degree. C., to prepare a
solution (40% by weight) of an acryl-based polymer (D). This
acryl-based polymer (D) had Tg=-55.degree. C., a weight average
molecular weight of 800 thousands, and an acid value of 0.0.
(Acryl-Based Polymer (E))
[0390] A four-neck flask equipped with a stirring wing, a
thermometer, a nitrogen gas introducing tube, a condenser, and a
dropping funnel was charged with 180 parts by weight of
2-ethylhexyl acrylate, 20 parts by weight of N,N-diethyl acryl
amide, 8 parts by weight of 2-hydroxyethyl acrylate, 0.4 part by
weight of 2,2'-azobisisobutyronitrile as a polymerization
initiator, and 312 parts by weight of ethyl acetate, a nitrogen gas
was introduced while mildly stirring, and a polymerization reaction
was performed for about 5 hours while maintaining a liquid
temperature in a flask at about 60.degree. C., to prepare a
solution (40% by weight) of an acryl-based polymer (E). This
acryl-based polymer (E) had Tg=-59.degree. C., a weight average
molecular weight of 610 thousands, and an acid value of 0.0.
(Acryl-Based Polymer (F))
[0391] A four-neck flask equipped with a stirring wing, a
thermometer, a nitrogen gas introducing tube, a condenser, and a
dropping funnel was charged with 200 parts by weight of
2-ethylhexyl acrylate, 8 parts by weight of 2-hydroxyethyl
acrylate, 0.4 part by weight of 2,2'-azobisisobutyronitrile as a
polymerization initiator, and 312 parts by weight of ethyl acetate,
a nitrogen gas was introduced while mildly stirring, and a
polymerization reaction was performed for about 5 hours while
maintaining a liquid temperature in a flask at about 60.degree. C.,
to prepare a solution (40% by weight) of an acryl-based polymer
(F). This acryl-based polymer (F) had Tg=-68.degree. C., a weight
average molecular weight of 550 thousands, and an acid value of
0.0.
[Preparation of Ionic Liquid]
(Ionic Liquid (1))
[0392] A 20% by weight aqueous solution of 10 parts by weight of
1-butyl-3-methylpyridinium chloride (manufactured by Wako Pure
Chemical Industries, Ltd.) was added to four-neck flask equipped
with a stirring wing, a thermometer, and a condenser, and a 20% by
weight aqueous solution of 19 parts by weight of lithium
bis(trifluoromethanesulfonyl)imide (manufactured by Kishida
Chemical Co., Ltd.) was gradually added while rotating a stirring
wing. After addition, stirring was continued at 25.degree. C. for 2
hours, and this was allowed to stand for 12 hours. Then, the
supernatant was removed to obtain a liquid product.
[0393] The resulting liquid product was washed with 200 parts by
weight of distilled water three times, and dried for 2 hours under
the environment of 110.degree. C. to obtain 20 parts by weight of
an ionic liquid (1) which is liquid at 25.degree. C. NMR (.sup.1H,
.sup.13C.) measurement, FT-IR measurement, and XRF measurement of
the resulting ionic liquid (1) were performed, and
1-butyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imide was
identified and confirmed.
[Preparation of Antistatic Agent Solution]
(Antistatic Agent Solution (a))
[0394] Ten parts by weight of the aforementioned ionic liquid (1),
and 90 parts by weight of ethyl acetate were put into a flask with
four openings provided with mixing blades, a thermometer, and a
condenser, and the mixture was stirred for 30 minutes while the
temperature of the liquid within the flask was maintained at
approximately room temperature (25.degree. C.), so that an
antistatic agent solution (a) (10% by weight) was prepared.
(Antistatic Agent Solution (b))
[0395] Five parts by weight of the aforementioned ionic liquid (1),
5 parts by weight of nonionic reactive surfactant (manufactured by
Asahi Denka Co., Ltd., ADEKA REASOAP ER-10), and 90 parts by weight
of ethyl acetate were put into a flask with four openings provided
with mixing blades, a thermometer, and a condenser, and the mixture
was stirred for 30 minutes while the temperature of the liquid
within the flask was maintained at approximately room temperature
(25.degree. C.), so that an antistatic agent solution (b) (10% by
weight) was prepared.
(Antistatic Agent Solution (c))
[0396] Ten parts by weight of N,N-diethyl-N-methyl-N-(2-methoxy
ethyl)ammonium bis(trifluoromethanesulfonyl)imide (manufactured by
Kanto Chemical Co., Inc, liquid at 25.degree. C.) and 90 parts by
weight of ethyl acetate were put into a flask with four openings
provided with mixing blades, a thermometer, and a condenser, and
the mixture was stirred for 30 minutes while the temperature of the
liquid within the flask was maintained at approximately room
temperature (25.degree. C.), so that an antistatic agent solution
(c) (10% by weight) was prepared.
(Antistatic Agent Solution (d))
[0397] A four-neck flask equipped with a stirring wing, a
thermometer, and a condenser was charged with 0.1 part by weight of
lithium iodide, 9.9 parts by weight of polypropylene glycol (diol
type, number average molecular weight: 2000), and 90 parts by
weight of ethyl acetate, and mixing and stirring were performed for
2 hours while maintaining a temperature of a liquid in a flask at
around 80.degree. C., to prepare an antistatic agent solution (d)
(10% by weight).
[Preparation of Antistatic-Treated Film]
(Antistatic-Treated Film)
[0398] The antistatic-treated film of Preparation Example in
Example II was used as an antistatic-treated film in Example I.
Example II-1
(Preparation of Pressure-Sensitive Adhesive Composition)
[0399] A solution (40% by weight) of the aforementioned acryl-based
polymer (A) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 3 parts by
weight of the antistatic agent solution (a) (10% by weight), 0.6
part by weight of an isocyanurate of hexamethylene diisocyanate
(manufactured by Nippon Polyurethane Industry Co., Ltd, Coronate
HX), and 0.4 part by weight of tin dibutyl dilaurate (1% by weight
ethyl acetate solution), which is a crosslinking catalyst, which
was mixed and stirred for approximately 1 minute at room
temperature (25.degree. C.), and whereby, an acryl
pressure-sensitive adhesive solution (1) was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0400] The aforementioned acryl pressure-sensitive adhesive
solution (1) was coated on a side opposite to an antistatic-treated
side of the antistatic-treated film obtained in Preparation
described above, and this was heated at 110.degree. C. for 3
minutes to form a pressure-sensitive adhesive layer having a
thickness of 20 .mu.m. Then, a silicone-treated side of a
polyethylene terephthalate film having a thickness of 25 .mu.m
which had been subjected to silicone-treated was laminated on one
side of a surface of the aforementioned pressure sensitive adhesive
layer to prepare a pressure-sensitive adhesive sheet.
Example II-2
(Preparation of Pressure-Sensitive Adhesive Composition)
[0401] A solution (40% by weight) of the aforementioned acryl-based
polymer (B) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 6 parts by
weight of the antistatic agent solution (b) (10% by weight), 0.6
part by weight of an isocyanurate of hexamethylene diisocyanate
(manufactured by Nippon Polyurethane Industry Co., Ltd, Coronate
HX), and 0.4 part by weight of tin dibutyl dilaurate (1% by weight
ethyl acetate solution), which is a crosslinking catalyst, which
was mixed and stirred for approximately 1 minute at room
temperature (25.degree. C.), and whereby, an acryl
pressure-sensitive adhesive solution (2) was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0402] According to the same manner as that of Example II-1 except
that the acryl pressure-sensitive adhesive solution (2) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Example II-3
(Preparation of Pressure-Sensitive Adhesive Composition)
[0403] A solution (40% by weight) of the aforementioned acryl-based
polymer (C) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 6 parts by
weight of the antistatic agent solution (b) (10% by weight), 0.6
part by weight of an isocyanurate of hexamethylene diisocyanate
(manufactured by Nippon Polyurethane Industry Co., Ltd, Coronate
HX), and 0.4 part by weight of tin dibutyl dilaurate (1% by weight
ethyl acetate solution), which is a crosslinking catalyst, which
was mixed and stirred for approximately 1 minute at room
temperature (25.degree. C.), and whereby, an acryl
pressure-sensitive adhesive solution (3) was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0404] According to the same manner as that of Example II-1 except
that the acryl pressure-sensitive adhesive solution (3) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Example II-4
(Preparation of Pressure-Sensitive Adhesive Composition)
[0405] A solution (40% by weight) of the aforementioned acryl-based
polymer (D) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 6 parts by
weight of the antistatic agent solution (b) (10% by weight), 0.6
part by weight of an isocyanurate of hexamethylene diisocyanate
(manufactured by Nippon Polyurethane Industry Co., Ltd, Coronate
HX), and 0.4 part by weight of tin dibutyl dilaurate (1% by weight
ethyl acetate solution), which is a crosslinking catalyst, which
was mixed and stirred for approximately 1 minute at room
temperature (25.degree. C.), and whereby, an acryl
pressure-sensitive adhesive solution (4) was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0406] According to the same manner as that of Example II-1 except
that the acryl pressure-sensitive adhesive solution (4) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Example II-5
(Preparation of Pressure-Sensitive Adhesive Composition)
[0407] A solution (40% by weight) of the aforementioned acryl-based
polymer (E) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 6 parts by
weight of the antistatic agent solution (a) (10% by weight), 0.6
part by weight of an isocyanurate of hexamethylene diisocyanate
(manufactured by Nippon Polyurethane Industry Co., Ltd, Coronate
HX), and 0.4 part by weight of tin dibutyl dilaurate (1% by weight
ethyl acetate solution), which is a crosslinking catalyst, which
was mixed and stirred for approximately 1 minute at room
temperature (25.degree. C.), and whereby, an acryl
pressure-sensitive adhesive solution (5) was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0408] According to the same manner as that of Example II-1 except
that the acryl pressure-sensitive adhesive solution (5) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Example II-6
(Preparation of Pressure-Sensitive Adhesive Composition)
[0409] A solution (40% by weight) of the aforementioned acryl-based
polymer (E) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 2 parts by
weight of the antistatic agent solution (c) (10% by weight), 0.6
part by weight of an isocyanurate of hexamethylene diisocyanate
(manufactured by Nippon Polyurethane Industry Co., Ltd, Coronate
HX), and 0.4 part by weight of tin dibutyl dilaurate (1% by weight
ethyl acetate solution), which is a crosslinking catalyst, which
was mixed and stirred for approximately 1 minute at room
temperature (25.degree. C.), and whereby, an acryl
pressure-sensitive adhesive solution (6) was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0410] According to the same manner as that of Example II-1 except
that the acryl pressure-sensitive adhesive solution (6) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Comparative Example II-1
(Preparation of Pressure-Sensitive Adhesive Composition)
[0411] A solution (40% by weight) of the aforementioned acryl-based
polymer (F) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 2 parts by
weight of the antistatic agent solution (a) (10% by weight), 0.6
part by weight of an isocyanurate of hexamethylene diisocyanate
(manufactured by Nippon Polyurethane Industry Co., Ltd, Coronate
HX), and 0.4 part by weight of tin dibutyl dilaurate (1% by weight
ethyl acetate solution), which is a crosslinking catalyst, which
was mixed and stirred for approximately 1 minute at room
temperature (25.degree. C.), and whereby, an acryl
pressure-sensitive adhesive solution (7) was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0412] According to the same manner as that of Example II-1 except
that the acryl pressure-sensitive adhesive solution (7) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Comparative Example II-2
(Preparation of Pressure-Sensitive Adhesive Composition)
[0413] A solution (40% by weight) of the aforementioned acryl-based
polymer (F) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 14 parts by
weight of the antistatic agent solution (d) (10% by weight), 0.6
part by weight of an isocyanurate of hexamethylene diisocyanate
(manufactured by Nippon Polyurethane Industry Co., Ltd, Coronate
HX), and 0.4 part by weight of tin dibutyl dilaurate (1% by weight
ethyl acetate solution), which is a crosslinking catalyst, which
was mixed and stirred for approximately 1 minute at room
temperature (25.degree. C.), and whereby, an acryl
pressure-sensitive adhesive solution (8) was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0414] According to the same manner as that of Example II-1 except
that the acryl pressure-sensitive adhesive solution (8) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Comparative Example II-3
(Preparation of Pressure-Sensitive Adhesive Composition)
[0415] A solution (40% by weight) of the aforementioned acryl-based
polymer (F) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 2.0 parts by
weight of an anionic surfactant, a sodium salt of dialkyl sulfo
succinate (manufactured by DAI-ICHI kogyo seiyaku CO., Ltd., NEOCOL
P), 1 part by weight of a trimethylolpropane/tolylene diisocyanate
trimer adduct (manufactured by Nippon Polyurethane Industry Co.,
Ltd, Coronate L, 75% by weight ethyl acetate solution), and 0.6
part by weight of tin dibutyl dilaurate (1% by weight ethyl acetate
solution), which is a crosslinking catalyst, which was mixed and
stirred for approximately 1 minute at room temperature (25.degree.
C.), and whereby, an acryl pressure-sensitive adhesive solution (9)
was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0416] According to the same manner as that of Example II-1 except
that the acryl pressure-sensitive adhesive solution (9) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
[0417] Regarding the pressure-sensitive adhesive sheets obtained in
the aforementioned Examples and Comparative Examples, a peeling
electrification voltage, staining property, an adhesive strength,
and occurrence of peeling off were assessed under the following
conditions.
<Measurement of Peeling Electrification Voltage>
[0418] Measurement of peeling electrification voltage in Example II
was measured as in Example I.
<Assessment of Staining Property>
[0419] A pressure-sensitive adhesive sheet was cut into a size of a
width of 50 mm and a length of 80 mm, a separator was peeled, and
this was adhered on a surface of a polarizing plate (SEG1425DU
manufactured by Nitto Denko Corporation, width: 70 mm, length: 100
mm), with a hand roller, to prepare an assessment sample.
[0420] The aformentioned assessment sample was allowed to stand for
24 hours under the environment 50.degree. C..times.92% RH, and then
for 2 hours under the environment 23.degree. C..times.50% RH, and,
thereafter, the pressure-sensitive adhesive sheet was peeled from
an adherend with a hand, and staining state of an adherend surface
thereupon was observed with naked eyes. Assessment criteria are as
follows:
[0421] Case of observation of no staining: .smallcircle.
[0422] Case of observation of staining: x
<Measurement of Adhesive Strength>
[0423] A pressure-sensitive adhesive sheet was cut into a size of a
width of 25 mm and a length of 100 mm, a separator was peeled, and
this was laminated on a polarizing plate (SEG1425DU manufactured by
Nitto Denko Corporation, width: 70 mm, length: 100 mm) with a
pressure of 0.25 MPa, to prepare an assessment sample.
[0424] After allowing to stand for 30 minutes under the environment
of 23.degree. C..times.50%RH after the lamination, an adhesive
strength when peeled with a universal tensile testing machine at a
peeling rate of 10 m/min and a peeling angle of 180.degree. was
measured. Measurement was performed under the environment of
23.degree. C..times.50% RH.
<Assessment of Occurrence of Peeling Off>
[0425] A pressure-sensitive adhesive sheet was cut into a size of a
width of 40 mm and a length of 40 mm, a separator was peeled, and
the resulting sheet was laminated on a polarizing plate
(SEG1425WVAGS2B manufactured by Nitto Denko Corporation, width: 70
mm, length: 100 mm) with a pressure of 0.25 MPa after a separator
was peeled off, to prepare an assessment sample.
[0426] After being laminated, the aforementioned assessment sample
was fixed to a slide glass (manufactured by Matsunami Glass Ind.,
Ltd., with clearly polished edges, thickness: 1.3 mm, width: 65 mm,
length: 165 mm), and an autoclave process was carried out for 20
minutes at 50.degree. C. under 5 atmospheres. After that, the
sample was left for 2 hours at 80.degree. C. at normal pressures,
and then, whether or not the pressure-sensitive adhesive sheet
peels from the polarizing plate was observed with naked eyes.
Assessment criteria are as follows:
[0427] In the case where the occurrence of peeling off was not
observed: .smallcircle.
[0428] In the case where the occurrence of peeling off was
observed: x
[0429] The results of the above are shown in Table 2.
TABLE-US-00002 TABLE 2 peeling staining adhesive occurrence
electrification property strength of peeling voltage [kV] [-] [N/25
mm] off [-] Example II-1 0.0 .smallcircle. 1.1 .smallcircle.
Example II-2 -0.1 .smallcircle. 1.1 .smallcircle. Example II-3 0.0
.smallcircle. 1.0 .smallcircle. Example II-4 0.0 .smallcircle. 1.3
.smallcircle. Example II-5 -0.1 .smallcircle. 1.8 .smallcircle.
Example II-6 0.0 .smallcircle. 1.4 .smallcircle. Comparative 0.0 x
0.6 x Example II-1 Comparative -0.2 x 0.4 x Example II-2
Comparative 0.0 x 0.4 x Example II-3
[0430] As can be seen from the results shown in the aforementioned
Table 2, in the case where the pressure-sensitive adhesive
composition manufactured in the present invention was used
(Examples II-1 to II-6), it is clear that the peeling
electrification voltage of a polarizing plate was suppressed,
staining on a polarizing plate, occurrence of peeling off did not
occur, and the adhesion reliance is excellent in any of the
Examples.
[0431] In contrast to this, in the case where a pressure-sensitive
adhesive composition that did not contain a nitrogen-containing
monomer as a monomer unit was used (Comparative Examples II-1 to
II-3), the results showed that in all cases, staining and
occurrence of peeling off were observed, although the peeling
electrification voltage was suppressed. Accordingly, in all of the
Comparative Examples, the results showed that suppression of the
peeling electrification voltage to the polarizing plate, which is
an adherend, as well as prevention of staining and the occurrence
of peeling off, and in addition to the excellent adhesion reliance
could not all be achieved at the same time.
Example III
<Measurement of Glass Transition Temperature Tg; Measurement of
a Dynamic Viscoelasticity>
[0432] The glass transition temperature (Tg) (.degree. C.) of the
resulting (meth)acryl-based polymer was determined based on the
measurement of a dynamic viscoelasticity described in Example I.
[Preparation of (meth)acryl-Based Polymers]
(Acryl-Based Polymer (A))
[0433] A four-neck flask equipped with a stirring wing, a
thermometer, a nitrogen gas introducing tube, a condenser, and a
dropping funnel was charged with 195 parts by weight of
2-ethylhexyl acrylate, 5 parts by weight of a nonionic reactive
surfactant (manufactured by Asahi Denka Co,. Ltd., Adeka Reasoap
ER-10), 8 parts by weight of 2-hydroxy ethyl acrylate, 0.4 part by
weight of 2,2'-azobisisobutyronitrile as a polymerization
initiator, and 312 parts by weight of ethyl acetate, a nitrogen gas
was introduced while mildly stirring, and a polymerization reaction
was performed for about 6 hours while maintaining a liquid
temperature in a flask at about 65.degree. C., to prepare a
solution (40% by weight) of an acryl-based polymer (A). This
acryl-based polymer (A) had Tg=-10.degree. C. or lower, a weight
average molecular weight of 680 thousands, and an acid value of
0.0.
(Acryl-Based Polymer (B))
[0434] A four-neck flask equipped with a stirring wing, a
thermometer, a nitrogen gas introducing tube, a condenser, and a
dropping funnel was charged with 200 parts by weight of
2-ethylhexyl acrylate, 8 parts by weight of 2-hydroxy ethyl
acrylate, 0.4 part by weight of 2,2'-azobisisobutyronitrile as a
polymerization initiator, and 312 parts by weight of ethyl acetate,
a nitrogen gas was introduced while mildly stirring, and a
polymerization reaction was performed for about 6 hours while
maintaining a liquid temperature in a flask at about 65.degree. C.,
to prepare a solution (40% by weight) of an acryl-based polymer
(B). This acryl-based polymer (B) had Tg=-10.degree. C. or lower, a
weight average molecular weight of 550 thousands, and an acid value
of 0.0.
(Acryl-Based Polymer (C))
[0435] A four-neck flask equipped with a stirring wing, a
thermometer, a nitrogen gas introducing tube, a condenser, and a
dropping funnel was charged with 198 parts by weight of
2-ethylhexyl acrylate, 2 parts by weight of a nonionic reactive
surfactant (manufactured by Asahi Denka Co,. Ltd., Adeka Reasoap
ER-10), 8 parts by weight of 2-hydroxy ethyl acrylate, 0.4 part by
weight of 2,2'-azobisisobutyronitrile as a polymerization
initiator, and 386 parts by weight of ethyl acetate, a nitrogen gas
was introduced while mildly stirring, and a polymerization reaction
was performed for about 5 hours while maintaining a liquid
temperature in a flask at about 60.degree. C., to prepare a
solution (35% by weight) of an acryl-based polymer (C). This
acryl-based polymer (C) had Tg=-10.degree. C. or lower, a weight
average molecular weight of 440 thousands, and an acid value of
0.0.
(Acryl-Based Polymer (D))
[0436] A four-neck flask equipped with a stirring wing, a
thermometer, a nitrogen gas introducing tube, a condenser, and a
dropping funnel was charged with 193 parts by weight of
2-ethylhexyl acrylate, 6 parts by weight of diacetone acryl amide,
1 part by weight of a nonionic reactive surfactant (manufactured by
Asahi Denka Co,. Ltd., Adeka Reasoap ER-10), 8 parts by weight of
2-hydroxy ethyl acrylate, 0.4 part by weight of
2,2'-azobisisobutyronitrile as a polymerization initiator, and 312
parts by weight of ethyl acetate, a nitrogen gas was introduced
while mildly stirring, and a polymerization reaction was performed
for about 5 hours while maintaining a liquid temperature in a flask
at about 60.degree. C., to prepare a solution (40% by weight) of an
acryl-based polymer (D). This acryl-based polymer (D) had
Tg=-10.degree. C. or lower, a weight average molecular weight of
650 thousands, and an acid value of 0.0.
(Acryl-Based Polymer (E))
[0437] A four-neck flask equipped with a stirring wing, a
thermometer, a nitrogen gas introducing tube, a condenser, and a
dropping funnel was charged with 193 parts by weight of
2-ethylhexyl acrylate, 6 parts by weight of acryloyl morpholine, 1
part by weight of a nonionic reactive surfactant (manufactured by
Asahi Denka Co,. Ltd., Adeka Reasoap ER-10), 8 parts by weight of
2-hydroxy ethyl acrylate, 0.4 part by weight of
2,2'-azobisisobutyronitrile as a polymerization initiator, and 312
parts by weight of ethyl acetate, a nitrogen gas was introduced
while mildly stirring, and a polymerization reaction was performed
for about 5 hours while maintaining a liquid temperature in a flask
at about 60.degree. C., to prepare a solution (40% by weight) of an
acryl-based polymer (E). This acryl-based polymer (E) had
Tg=-10.degree. C. or lower, a weight average molecular weight of
600 thousands, and an acid value of 0.0.
(Acryl-Based Polymer (F))
[0438] A four-neck flask equipped with a stirring wing, a
thermometer, a nitrogen gas introducing tube, a condenser, and a
dropping funnel was charged with 193 parts by weight of
2-ethylhexyl acrylate, 6 parts by weight of N,N-diethyl acryl
amide, 1 part by weight of a nonionic reactive surfactant
(manufactured by Asahi Denka Co,. Ltd., Adeka Reasoap ER-10), 8
parts by weight of 2-hydroxy ethyl acrylate, 0.4 part by weight of
2,2'-azobisisobutyronitrile as a polymerization initiator, and 312
parts by weight of ethyl acetate, a nitrogen gas was introduced
while mildly stirring, and a polymerization reaction was performed
for about 5 hours while maintaining a liquid temperature in a flask
at about 60.degree. C., to prepare a solution (40% by weight) of an
acryl-based polymer (F). This acryl-based polymer (F) had
Tg=-10.degree. C. or lower, a weight average molecular weight of
620 thousands, and an acid value of 0.0.
[Preparation of Ionic Liquids]
(Ionic Liquid (1))
[0439] A 20% by weight aqueous solution of 10 parts by weight of
1-butyl-3-methylpyridinium chloride (manufactured by Wako Pure
Chemical Industries, Ltd.) was added to four-neck flask equipped
with a stirring wing, a thermometer, and a condenser, and a 20% by
weight aqueous solution of 19 parts by weight of lithium
bis(trifluoromethanesulfonyl)imide (manufactured by Kishida
Chemical Co., Ltd.) was gradually added while rotating a stirring
wing. After addition, stirring was continued at 25.degree. C. for 2
hours, and this was allowed to stand for 12 hours. Then, the
supernatant was removed to obtain a liquid product.
[0440] The resulting liquid product was washed with 200 parts by
weight of distilled water three times, and dried for 2 hours under
the environment of 110.degree. C. to obtain 20 parts by weight of
an ionic liquid (1) which is liquid at 25.degree. C. NMR (.sup.1H,
.sup.13C) measurement, FT-IR measurement, and XRF measurement of
the resulting ionic liquid (1) were performed, and
1-butyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imide was
identified and confirmed.
[Preparation of Antistatic Agent Solutions]
(Antistatic Agent Solution (a))
[0441] Ten parts by weight of lauryl trimethyl ammonium chloride
(manufactured by Tokyo Kasei Kogyo Co., Ltd., solid at 25.degree.
C.) which is a cationic surfactant was distilled with 20 parts by
weight of ethyl acetate and 20 parts by weight of isopropyl
alcohol, and whereby, an antistatic agent solution (a) (20% by
weight) was prepared.
(Antistatic Agent Solution (b))
[0442] A four-neck flask equipped with a stirring wing, a
thermometer, and a condenser was charged with 0.2 part by weight of
lithium perchlorate, 9.8 parts by weight of polypropylene glycol
(diol type, number average molecular weight: 2000), and 10 parts by
weight of ethyl acetate, and mixing and stirring were performed for
2 hours while maintaining a temperature of a liquid in a flask at
around 80.degree. C., to prepare an antistatic agent solution (b)
(50% by weight).
[Preparation of Antistatic-Treated Film]
(Antistatic-Treated Film)
[0443] The antistatic-treated film of Preparation Example in
Example III was used as an antistatic-treated film in Example
I.
Example III-1
(Preparation of Pressure-Sensitive Adhesive Composition)
[0444] A solution (40% by weight) of the aforementioned acryl-based
polymer (A) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 0.2 part by
weight of the aforementioned ionic liquid (1), 0.4 part by weight
of an isocyanurate of hexamethylene diisocyanate (manufactured by
Nippon Polyurethane Industry Co., Ltd, Coronate HX), and 0.4 part
by weight of tin dibutyl dilaurate (1% by weight ethyl acetate
solution), which is a crosslinking catalyst, which was mixed and
stirred for approximately 1 minute at room temperature (25.degree.
C.), and whereby, an acryl pressure-sensitive adhesive solution (1)
was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0445] The aforementioned acryl pressure-sensitive adhesive
solution (1) was coated on a side opposite to an antistatic-treated
side of the antistatic-treated film obtained in Preparation
described above, and this was heated at 110.degree. C. for 3
minutes to form a pressure-sensitive adhesive layer having a
thickness of 20 .mu.m. Then, a silicone-treated side of a
polyethylene terephthalate film having a thickness of 25 .mu.m
which had been subjected to silicone-treated was laminated on one
side of a surface of the aforementioned pressure sensitive adhesive
layer to prepare a pressure-sensitive adhesive sheet.
Example III-2
(Preparation of Pressure-Sensitive Adhesive Composition)
[0446] A solution (35% by weight) of the aforementioned acryl-based
polymer (C) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 0.12 part by
weight of the fatty amine based ionic liquid (manufactured by KOEI
Chemical Co., Ltd, IL-A5, liquid at 25.degree. C.), 0.4 part by
weight of an isocyanurate of hexamethylene diisocyanate
(manufactured by Nippon Polyurethane Industry Co., Ltd, Coronate
HX), and 0.4 part by weight of tin dibutyl dilaurate (1% by weight
ethyl acetate solution), which is a crosslinking catalyst, which
was mixed and stirred for approximately 1 minute at room
temperature (25.degree. C.), and whereby, an acryl
pressure-sensitive adhesive solution (2) was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0447] According to the same manner as that of Example III-1 except
that the acryl pressure-sensitive adhesive solution (2) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Example III-3
(Preparation of Pressure-Sensitive Adhesive Composition)
[0448] A solution (40% by weight) of the aforementioned acryl-based
polymer (D) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 0.14 part by
weight of the aforementioned ionic liquid (1), 0.6 part by weight
of an isocyanurate of hexamethylene diisocyanate (manufactured by
Nippon Polyurethane Industry Co., Ltd, Coronate HX), and 0.4 part
by weight of tin dibutyl dilaurate (1% by weight ethyl acetate
solution), which is a crosslinking catalyst, which was mixed and
stirred for approximately 1 minute at room temperature (25.degree.
C.), and whereby, an acryl pressure-sensitive adhesive solution (3)
was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0449] According to the same manner as that of Example III-1 except
that the acryl pressure-sensitive adhesive solution (3) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Example III-4
(Preparation of Pressure-Sensitive Adhesive Composition)
[0450] An acryl pressure-sensitive adhesive solution (4) was
prepared in the same manner as in Example III-3, except that a
solution (40% by weight) of the aforementioned acryl based polymer
(E) was used in place of a solution (40% by weight) of the
aforementioned acryl-based polymer (D).
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0451] According to the same manner as that of Example III-1 except
that the acryl pressure-sensitive adhesive solution (4) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Example III-5
(Preparation of Pressure-Sensitive Adhesive Composition)
[0452] A solution (40% by weight) of the aforementioned acryl-based
polymer (F) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 0.2 part by
weight of the aforementioned ionic liquid (1), 0.6 part by weight
of an isocyanurate of hexamethylene diisocyanate (manufactured by
Nippon Polyurethane Industry Co., Ltd, Coronate HX), and 0.4 part
by weight of tin dibutyl dilaurate (1% by weight ethyl acetate
solution), which is a crosslinking catalyst, which was mixed and
stirred for approximately 1 minute at room temperature (25.degree.
C.), and whereby, an acryl pressure-sensitive adhesive solution (5)
was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0453] According to the same manner as that of Example III-1 except
that the acryl pressure-sensitive adhesive solution (5) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Comparative Example III-1
(Preparation of Pressure-Sensitive Adhesive Composition)
[0454] A solution (40% by weight) of the aforementioned acryl-based
polymer (B) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 0.2 part by
weight of the aforementioned ionic liquid (1), 0.4 part by weight
of an isocyanurate of hexamethylene diisocyanate (manufactured by
Nippon Polyurethane Industry Co., Ltd, Coronate HX), and 0.4 part
by weight of tin dibutyl dilaurate (1% by weight ethyl acetate
solution), which is a crosslinking catalyst, which was mixed and
stirred for approximately 1 minute at room temperature (25.degree.
C.), and whereby, an acryl pressure-sensitive adhesive solution (6)
was prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0455] According to the same manner as that of Example III-1 except
that the acryl pressure-sensitive adhesive solution (6) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Comparative Example III-2
(Preparation of Pressure-Sensitive Adhesive Composition)
[0456] An acryl pressure-sensitive adhesive solution (7) was
prepared in the same manner as in Example III-2, except that a
solution (40% by weight) of the aforementioned acryl based polymer
(B) was used in place of a solution (35% by weight) of the
aforementioned acryl-based polymer (C).
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0457] According to the same manner as that of Example III-1 except
that the acryl pressure-sensitive adhesive solution (7) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Comparative Example III-3
(Preparation of Pressure-Sensitive Adhesive Composition)
[0458] An acryl pressure-sensitive adhesive solution (8) was
prepared in the same manner as in Example III-1, except that the
aforementioned ionic liquid (1) was not used.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0459] According to the same manner as that of Example III-1 except
that the acryl pressure-sensitive adhesive solution (8) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Comparative Example III-4
(Preparation of Pressure-Sensitive Adhesive Composition)
[0460] An acryl pressure-sensitive adhesive solution (9) was
prepared in the same manner as in Example III-1, except that 1 part
by weight of the aforementioned antistatic agent solution (a) (20%
by weight) was used in place of 0.2 part by weight of the
aforementioned ionic liquid (1).
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0461] According to the same manner as that of Example III-1 except
that the acryl pressure-sensitive adhesive solution (9) was used in
place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
Comparative Example III-5
(Preparation of Pressure-Sensitive Adhesive Composition)
[0462] A solution (40% by weight) of the aforementioned acryl-based
polymer (B) was distilled to 20% by weight with ethyl acetate, and
to 100 parts by weight of this solution were added 4 parts by
weight of the aforementioned antistatic agent solution (b) (50% by
weight), 0.53 part by weight of a trimethylolpropane/tolylene
diisocyanate trimer adduct (manufactured by Nippon Polyurethane
Industry Co., Ltd, Coronate L), and 0.4 part by weight of tin
dibutyl dilaurate (1% by weight ethyl acetate solution), which is a
crosslinking catalyst, which was mixed and stirred for
approximately 1 minute at room temperature (25.degree. C.), and
whereby, an acryl pressure-sensitive adhesive solution (10) was
prepared.
(Preparation of Pressure-Sensitive Adhesive Sheet)
[0463] According to the same manner as that of Example III-1 except
that the acryl pressure-sensitive adhesive solution (10) was used
in place of an acryl pressure-sensitive adhesive solution (1), a
pressure-sensitive adhesive sheet was prepared.
[0464] Regarding the pressure-sensitive adhesive sheets obtained in
the aforementioned Examples and Comparative Examples, a peeling
electrification voltage, staining property, and an adhesive
strength were assessed under the following conditions.
<Measurement of Peeling Electrification Voltage>
[0465] A pressure-sensitive adhesive sheet was cut into a size of a
width of 70 mm and a length of 130 mm, a separator was peeled, and
this was adhered to a surface of a polarizing plate (SEG1425EWVGS2B
manufactured by Nitto Denko Corporation, width: 70 mm, length: 100
mm) laminated to an acryl plate (Acrylite manufactured by
Mitsubishi Rayon Co., Ltd, thickness: 1 mm, width: 70 mm, length:
100 mm) from which electricity had been removed in advance, with a
hand roller, so that one end was protruded by 30 mm.
[0466] After allowed to stand for one day under the environment of
23.degree. C..times.50% RH, and a sample was set at a prescribed
position as shown in FIG. 1. One end protruding by 30 mm was fixed
on an automatic winding machine, and a sample was peeled at a
peeling angle of 150.degree. and a peeling rate of 10 m/min. A
voltage at a polarizing plate surface generated thereupon was
measured with an electrostatic voltmeter (KSD-0103 manufactured by
Kasuga Denka, INC.) fixed at a prescribed position. Measurement was
performed under the environment of 23.degree. C..times.50% RH.
<Assessment of Staining Property>
[0467] A pressure-sensitive adhesive sheet was cut into a size of a
width of 30 mm and a length of 80 mm, a separator was peeled, and
this was adhered on a surface of a polarizing plate (SEG1425DU
manufactured by Nitto Denko Corporation, width: 70 mm, length: 100
mm), with a hand roller, to prepare an assessment sample.
[0468] The aformentioned assessment sample was allowed to stand for
a month under the environment 25.degree. C..times.50% RH, and,
thereafter, the pressure-sensitive adhesive sheet was peeled from
an adherend with a hand, and staining state of an adherend surface
thereupon was observed with naked eyes. Assessment criteria are as
follows:
[0469] Case of observation of no staining: .smallcircle.
[0470] Case of observation of staining: x
<Measurement of Adhesive Strength>
[0471] Measurement of adhesive strength in Example III was measured
as in Example I.
[0472] The results of the above are shown in Table 3.
TABLE-US-00003 TABLE 3 peeling staining adhesive electrification
property strength voltage [kV] [-] [N/25 mm] Example III-1 -0.1
.smallcircle. 1.2 Example III-2 0.0 .smallcircle. 1.5 Example III-3
-0.3 .smallcircle. 0.9 Example III-4 -0.1 .smallcircle. 1.0 Example
III-5 0.0 .smallcircle. 1.0 Comparative 0.0 x 1.6 Example III-1
Comparative 0.0 x 1.7 Example III-2 Comparative -1.1 .smallcircle.
1.4 Example III-3 Comparative 0.0 x 0.3 Example III-4 Comparative
0.0 x 0.5 Example III-5
[0473] As can be seen from the results shown in the aforementioned
Table 3, in the case where the pressure-sensitive adhesive
composition manufactured in the present invention was used
(Examples III-1 to III-5), it is clear that the peeling
electrification voltage of a polarizing plate was suppressed, and
staining on a polarizing plate did not occur in any of the
Examples.
[0474] In contrast to this, in the case where the
pressure-sensitive adhesive composition that did not contain a
reactive surfactant as a monomer unit of the base polymer was used
(Comparative Examples III-1 and III-2), in all cases, the results
showed that staining was observed, although the peeling
electrification voltage was suppressed. In addition, in the case
where a pressure-sensitive adhesive composition that did not
contain an ionic liquid was used (Comparative Example III-3), the
results showed that the peeling electrification voltage to the
polarizing plate, which is an adherend, was high, although no
staining was found. Furthermore, in the case where a cation type
surfactant was used as an antistatic agent (Comparative Example
III-4) and in the case where an alkali metal salt and polyether
polyol were used (Comparative Example III-5), the results showed
that staining was observed, although the peeling electrification
voltage was suppressed. Accordingly, in all of the Comparative
Examples, the results showed that suppression of the peeling
electrification voltage to the polarizing plate, which is an
adherend, and prevention of staining could not both be achieved,
and it became clear that these Comparative Examples were not
appropriate as a pressure sensitive adhesive composition for an
antistatic pressure-sensitive adhesive sheet.
* * * * *